Boxing fights we always wanted to see, but never happened. Add Spence-Crawford to the list?

A megafight between Floyd Mayweather, left, and Antonio Margarito was discussed in 2006. ESPN

Errol Spence Jr. and Terence Crawford were on the verge of a deal for an undisputed welterweight championship fight in November, but with talks stalled, and Crawford agreeing to a fight against David Avanesyan on Dec. 10, it's unclear if they'll ever meet in a ring, let alone next.

Tyson Fury and Anthony Joshua teased a Dec. 3 bout that could've been the biggest boxing fight in U.K. history, but instead, fans will have to settle for The Gypsy King in a tune-up trilogy bout against Derek Chisora ahead of a probable spring bout with Oleksandr Usyk for the undisputed heavyweight championship.

If boxing can deliver Fury-Usyk, that would be the rare superfight when both boxers are at the peak of their powers. There's also hope a deal can be struck to pit lightweights Ryan Garcia against Gervonta Davis in perhaps the biggest commercial event the sport can offer in the U.S. And there's still time -- if little -- for Spence and Crawford to come to terms before the matchup is past its expiration date.

But what about all the bouts that fell by the wayside over the years? Those super fights that were obvious massive money makers for the sport, and the fighters, yet never happened for one reason or another. There are countless examples, sadly, of the sport depriving its fans of some tasty matchups at the apex of its commercial interest.

ESPN looks at seven fights that should have happened (but never did). Each matchup received a viability score out of 30, with 10 points tied to just how much the public clamored for the fight at the time, another 10 tied to how much money the event might have pulled in and 10 more connected to how much sense the bout made for the fighters. The potential superfights are ranked in that order.

Mike Tyson vs. George Foreman

Viability score: 28
Fan interest: 10
Money making potential: 10
Fighter interest: 8

A moneymaking bonanza for the ages. A bout between two of the greatest -- and most popular -- heavyweights of all time was actually in play in 1990.

After Tyson was knocked out by James "Buster" Douglas in the biggest upset in boxing history, he shared a doubleheader with George Foreman. Both men were on the comeback trail, with Tyson looking to rebuild from his first career loss, and Foreman attempting a second heavyweight title run in his 40s. Tyson scored a first-round KO of Henry Tillman in his first fight after the loss to Douglas, while Foreman stopped Gerry Cooney in the second round in January 1990 in Atlantic City.

Tyson and Foreman appeared to be on a collision course, but it wasn't meant to be. "Iron" Mike went on to face Razor Ruddock in a pair of fights before his prison stint for a rape conviction, while Foreman lost a decision to Evander Holyfield the following year in a heavyweight epic that proved he was still elite all those years later.

"Big" George, of course, ended up winning the heavyweight championship years later in one of sports' greatest comebacks. Still, he wanted no part of Tyson, Foreman told ESPN's Max Kellerman in 2020.

Anthony Joshua vs. Deontay Wilder

Viability score: 26
Fan interest: 9
Money making potential: 9
Fighter interest: 8

This one will hopefully still happen, but even if it does, it will never be as big as it could have been.

When it was first being discussed in 2018, Joshua was perhaps the biggest star in global boxing. He held three titles and Fury was still retired at the time. Joshua had also an argument to be perhaps the second-most-imposing puncher in all of boxing. No. 1 was -- and remains -- Deontay Wilder.

The deal fell apart over network issues -- Wilder was aligned with Showtime and Joshua with DAZN -- along with promotional allegiances. Later that year, Wilder fought to a split draw with Fury while Joshua was upset by Andy Ruiz Jr. in June 2019.

Joshua regained the titles in the rematch with Ruiz, but he hasn't shown the same ferocity (or trust in his chin). Now, he's coming off back-to-back losses to Usyk, while Wilder is back in the win column with a first-round KO over former sparring partner Robert Helenius following a pair of brutal beatings at the hands of Fury.

If Joshua-Wilder is revisited, it's still a superfight, but it will never match up to the allure of what once was.

Erik Morales vs. Juan Manuel Marquez

Viability score: 25
Fan interest: 9
Money making potential: 7
Fighter interest: 9

Of all the matchups on this list, the failure to make Morales-Marquez might be the most surprising.

After all, Morales, Marquez, Marco Antonio Barrera and Manny Pacquiao combined to fight each other 13 times. Somehow, they all faced one another in the ring with the exception of Morales and Marquez, two legendary Mexican fighters who could box, slug and found their best success at featherweight.

There was ample time to manifest this matchup, with both boxers hovering around each other's weight for years. Morales and Marquez both climbed all the way to 147 pounds and were still top-notch fighters at advanced ages.

A deal for a 140-pound fight in 2011 seemed close, but we were left wondering "what if" instead. At least we have the memories of each man's epic fight with Pacquiao, along with Morales' all-time trilogy with Barrera.

Canelo Alvarez vs. Andre Ward

Ward: I'm not coming out of retirement to fight Alvarez

Despite outside pressure, Andre Ward says he is not coming out of retirement to fight Canelo Alvarez.

Viability score: 24
Fan interest: 10
Money making potential: 10
Fighter interest: 4

Before Alvarez decided to jump up to 175 pounds for a title fight with Sergey Kovalev in November 2019, DAZN explored a fight between the Mexican star and Ward, a two-division undefeated champion who was two years into retirement but still just 35.

The bout would have pitted the sport's pound-for-pound king, Alvarez, against the former No. 1 P4P fighter who held the light heavyweight throne for years before retirement in Ward. And it would have been a fascinating, coin-flip matchup.

Ward was the naturally bigger man and with his defensive excellence and ring smarts, could have all the tools to neutralize Alvarez's offense just like Floyd Mayweather did, but in a different manner.

On the other hand, Ward would have been coming off a two-year layoff against a fighter on a tear and at the peak of his powers. Alvarez impressed in two fights with Gennady Golovkin at 160 pounds and would have owned a six-year age advantage.

Ward was approached by DAZN with the idea of fighting Alvarez, but he didn't show interest in coming out of retirement. After all, he retired on top and has enjoyed a role as a boxing analyst for ESPN. Alvarez, meanwhile, went on to knock out Kovalev before a dominant run at 168 pounds.

Sergey Kovalev vs. Adonis Stevenson

Viability score: 23
Fan interest: 8
Money making potential: 6
Fighter interest: 9

Two ferocious light heavyweight punchers in a title unification? The fight appeared to be a no-brainer, but as usual, boxing politics had other ideas.

Stevenson scored a first-round KO of Chad Dawson in 2013 to win the WBC and lineal light heavyweight championship. Two months later, Kovalev won the WBO title with a fourth-round TKO of Nathan Cleverly. Suddenly, the calls for a summit meeting at 175 pounds began.

There was still time to "marinate" the matchup and make it even bigger, and that's exactly what happened as both Kovalev and Stevenson went on to score a plethora of punishing knockouts.

They circled each other for years at the top of the light heavyweight division, and the rivalry grew ugly when Russia's Kovalev made racist remarks about Stevenson. Despite all the interest in the fight, Kovalev's promoter, Main Events, and PBC, Stevenson's promoter, couldn't come to terms on the fight.

Kovalev went on to lose a pair of fights against Andre Ward, while Stevenson tragically suffered a head injury in a 2018 loss to Oleksandr Gvozdyk and was forced to retire afterward.

Riddick Bowe vs. Lennox Lewis

Viability score: 22
Fan interest: 8
Money making potential: 7
Fighter interest: 7

With Tyson in prison, Riddick Bowe took over the heavyweight division in the early 1990s. He outpointed Holyfield in November 1992 to win the undisputed heavyweight championship, but there was one can't-miss opponent for Bowe who remained: Lennox Lewis.

Lewis wasn't yet a star when he was named the WBC's mandatory challenger to Bowe, but they already had history together. Lewis defeated Bowe in the Olympic gold medal match in 1988 in Seoul, South Korea, and was well on his way to taking over the pros, too.

Rather than face Lewis next, "Big Daddy" Bowe threw the WBC title in the trash at a news conference in December 1992. He still held the WBA and IBF belts (the WBO wasn't recognized then) before the WBC formally stripped him one month later.

Lewis went on to win the vacant title from Tony Tucker in 1993 while Bowe had two more fights with Holyfield in one of the greatest trilogies in boxing history. The fight could have been revisited after Lewis avenged his upset defeat to Oliver McCall in 1997, but by that point, Bowe had already retired following two infamous DQ wins over Andrew Golota, the latter of which spurred the SWAT team's involvement at Madison Square Garden.

Floyd Mayweather vs. Antonio Margarito

Viability score: 22
Fan interest: 8
Money making potential: 7
Fighter interest: 7

Before he was known as "Money" Mayweather, the all-time great was simply "Pretty Boy" Floyd, a virtuoso boxer at the peak of his powers.

Mayweather made his move to welterweight in 2006 with a decision victory over Zab Judah to claim a title in a fourth weight class, which led to calls for a fight with Antonio Margarito. A 5-foot-11 147-pounder who often threw upward of 1,000 punches per fight, Margarito appeared to present a stylistic challenge for Mayweather.

Surely, Margarito wouldn't have been favored to defeat Mayweather -- who was? -- but he would have likely made for a fun action fight. Top Rank promoted both Mayweather and Margarito, and with boxing's large Mexican fan base, the company looked to capitalize by matching them together later in '06.

Bob Arum offered Mayweather $8 million for the assignment, a then career-best payday, but Mayweather had other ideas. Instead, he bought out his contract with Top Rank for $750,000 and took a far easier fight against Carlos Baldomir.

The gamble to leave Top Rank paid off handsomely. The following year, Mayweather fought Oscar De La Hoya in what was then the richest fight in boxing history (surpassed by Floyd's fights with Pacquiao and Conor McGregor) and he became the most bankable fighter in history.

The Tijuana Tornado went on to defeat Miguel Cotto in a brutal welterweight title fight in 2008, but Margarito's career was forever marred when the ingredients for plaster of Paris were discovered in his hand wraps prior to his TKO loss to Shane Mosley later that year.