I dont think you can compare TF2 to football. People who watch esports have wildly different motivations for watching than people who watch football.
People bring up the stale meta of tf2 as a problem because they are looking towards actual successful, modern-day esports. Specifically, league of legends and dota. Even CS has a lot of variation. Valve has recently started adding a bunch of new maps and balance changes, while the CS scene has been mysteriously exploding.
Maybe at some point people will obsess over esports and esports teams the way people care about real life sports, but we are not there yet, and TF2 isnt going to take us there.