Your fairy tale ignores the fact that the club invested a lot of money to recover from the bad season 2006/07. Also, 10 years ago, prices were much lower, which shows that Bayern was a leading investor on the transfers market
Summer 07: they took Ribéry, Klose, Luca Toni, Altintop, Ze Roberto and promoted a guy whose name is Kroos. Total spending: 92M
Summer 08: they just recruited 2 squad players (Donova, Borowski) for free. Total spending: 0 million
Summer 09: they took Robben (24 millions), Mario Gomez (35 m), Olic, Tymsochuk Total spending: 79.7 million