It's the same reason why you DO NOT WANT a committee or playoff. Let the AP and Coaches have their own polls and go back to what worked and decide the title by those polls. If you have a split title, then so be it. When you had the Holiday Bowl, it still meant something. College football was at its best in these days, even with 2 titles on occasion. The drama was popular. Humans will always error and that's ok, but more important is.........there are some humans who are corrupt and will not do the right thing. That's not ok, but it will not change. This includes humans picking their team over another team to play in a playoff. The same applies to the AP and Coaches Poll, but with the AP and Coaches Poll, you have far, far more people compared to a small committee and you get a washout effect. Washout effect meaning........statistically, you know there are going to be those who are corrupt or not 100% objective, but you hope to attenuate that by having a large statistical sample to overcome the non-objectivity. When you have a smaller sample volume (the current committee), you get more non-objectivity or error, corruption, or whatever one wishes to call it coming to the surface. Thus, it weakens college football.
