We should consider the 2000s Lions as not only one of the worst teams in NFL history, but one of the worst teams in professional sports history. The Lions began the decade with a 9-7 record and have proceeded to go 33-110 (.231 win pct) since then. Entering this weekend, the Lions are 42-117 in the 2000s (.264 win pct). Let's put this in perspective -- they have 14 fewer wins than the Cleveland Browns during that time and the Browns have the second worst record at 56-103 (.352 win pct).
The Lions are not keeping good company. Below are the other "leaders" for most losses in a decade in the four major professional sports. Being mentioned with the 1980s Clippers is never something your team aspires to.
Most losses in any decade for the 4 pro sports leagues
The .264 win percentage for the Lions this decade is not just bad, it will go down as the worst in NFL history with a minimum of 100 games played. Sorry, 1970s Saints and 1980s Buccaneers, your spot in history will be supplanted by the 2000s Lions.
Worst win percentage in any decade in NFL