Because for some inexplicable reason the NCAA, which oversees all other collegiate sports and even football at the lower levels, has seen fit to farm out the decision making of collegiate football at its highest level since 1936. And even until the BCS/CFP era there was not always a consensus then with many split championships.
I don't know why this is but the NCAA has never actually awarded a National Championship for Division 1/FBS football. They even have a page on their website describing the history of the process from the late 1890s to the present but offer no explanation why.
Anybody know?
Again, too many teams and not enough games. In the old days, teams used to play only 9-10 games a season. It's not like basketball or baseball, where you play 30-40 games, and you can play multiple games in a week, making it easier to stage tournaments. Plus, the bowl system has been around since the turn of last century. By the time the NCAA started hosting tournaments, the bowl system had been well established, and there was more money in the bowl games than in a tournament.
The problem with football is there is such a disparity between the big schools and the small schools. In basketball, you only need 12 players, so it's easy for the small schools to compete. With football, you need 60-80 players. It's hard for the smaller schools to support that many players, so the best talent disproportionately ends up at the big schools. So in other words, if you had a conference-winners tournament, you would have South Florida, Western Kentucky, Western Michigan, San Diego St, and Troy all in a tournament, and you would have Ohio St, Baylor, West Virginia, Texas A&M, Florida, and Nebraska all sitting at home. Good luck getting the P5 or ESPN to agree to that.
You also have to remember that playoffs themselves were not very common back then. The NFL itself did not have playoffs until 1933.
