The best football being played is the NFL. Best athletes, best skills, best football. A level-playing field (at least pretty close) and major share in places like the Northeast.
College football is about relationships---with the school and with the community. Good players, good skills, but nowhere near the level of the NFL.
If people want the best football, they'll watch the NFL. If people desire a relationship with their alma mater and their community, they'll watch college football.
But the number of people that are interested in watching semi-pro football and root for players at a school or community that they don't have a relationship with, is not high.
Will I watch the NFL playoffs where teams that I don't normally cheer for are playing? Sure, because the football is great and the level of parity in the NFL assures that there are going to be some amazing games.
Will I watch a playoff game between Alabama and Georgia if they have created a league that excludes my college team and community? Nope. No interest in watching a game that has no relevance for the school I care about and no interest in watching a game that has semi-pro players.
I think we're at the point where the SEC and B10 are about to kill the goose that laid the golden egg. The situation is almost the exact opposite of what was so beautifully portrayed in Field of Dreams. In that case, the people will "most definitely come". In the case of the SEC/B10 split off, I believe that people will "most definitely check out".