Barca beat Bayern in the Champions League semifinals on their way to the Treble in 2015 but have been on the decline ever since and the German side have won the last two meetings between the sides by an aggregate score of 11-2.
Barca travel to Munich this week in danger of being knocked out of the Champions League in the group stages for the first time since 2000 if they fail to register a win.
"The running of the club, it's as simple as that," Pique said bluntly when asked why Bayern, who have already qualified for the last 16, have been so much better than Barca in recent years.
Bayern won the Champions League in 2020 after beating Barca 8-2 in the quarterfinal, while they have also won nine Bundesliga titles in a row. Barca have only won the Copa del Rey in the last two years.
Pique has implicitly blamed former president Josep Maria Bartomeu for Barca's decline before and he ranked him among the club's worst-ever presidents in an interview in September.
Joan Laporta's return as Bartomeu's successor in March represented a fresh start, but he inherited a club steeped in debt, which has had a knock-on effect on the pitch this season.
Barca can book their place in the last 16 of the Champions League by winning in Munich, but if they fail to do so, and Benfica better their result at home to Dynamo Kiev, they will drop into the Europa League in the New Year.
"We are playing for our lives," Pique added. "We can reaffirm to ourselves that we can compete in Europe's top competition. The last two games against Bayern didn't go as we hoped, but that's in the past."
Barca go into the game on the back of a 1-0 defeat to Real Betis which left them seventh in LaLiga, but Pique said there have been positives since Xavi Hernandez replaced Ronald Koeman as coach in November.
"We could be here for hours talking about the situation we're in, but we have to focus on the present and the future," the defender said.
"We're seeing things now -- such as recovering the ball high, pressing after losing the ball, intensity, hunger -- that are necessary to win trophies. From there, goals and performances will arrive, but it doesn't change overnight."
Barca face a Bayern side that have scored 19 goals in their five Champions League games this season, with Robert Lewandowski (27) responsible for more goals than Barca (25) in all competitions in this term.
The German side will be without Joshua Kimmich, Leon Goretzka and Serge Gnabry for the game, but coach Julian Nagelsmann says they will field a strong side even though they have already secured top place in the group.
Xavi, who has won two, drawn one and lost one of his first four matches in charge, said he is looking forward to the challenge as Barca seek a first-ever win in Munich.
"Bayern are one of the worst opponents we could face," Xavi said. "They are one of the best teams in the world and we're playing at their ground. It will be extremely difficult.
"If we win, we're through, which means it's a final. History says that we have never won in Munich, but records are there to be broken and we can't wait for the game to start."
Barca are still without Ansu Fati, Pedri, Sergio Aguero and Martin Braithwaite for the game, which will be played behind closed doors due to coronavirus restrictions in Germany, but Xavi said Ousmane Dembele is "100%" and Jordi Alba should shake off a knock.