How come no number one ranked college team can manage to stay there

A big trend seems to be growing in the world of college basketball, no number one team can stay ranked that for more than a week. I don't know if we should credit this to more parody among the teams and the talent pool across the country is evening out or these young men get the big head and lose focus. I think it is probably a combination of both, the talent on teams has gotten a lot better but these young players start believing the hype from all the people on campus and run into a buzz saw. The fact that the other team knows they are playing the number ranked team may play a part too because we all know everyone gets up to play number one, and number one should know that they are wearing a huge bullseye. Maybe what this is really saying is, that rankings are over rated and they don't matter until the last one comes out mid april.