What do you have to play for after you lose a game?
You're playing on national TV in front of a million plus eyeballs. You play hard to not get humiliated in front of the country.
You play hard to get ranked.
You play hard to not get benched.
You play hard because you've played football your whole life and you want to win every game, even if you lost the game before.
You play hard because you want to make all the off season work and practices and sacrifices worth it.
You play hard because your friends and rivals from high school went to neighboring universities and you don't want to look like a chump compared to them.
Indy life isn't perfect but I don't believe the "nothing to play for" idea is a real thing.