Depending on how far you want to go back, football is a bigger financial deal to colleges and universities than probably any time in the past. Someone probably made a (very) coldly calculated choice to cover it up. If there weren't millions of dollars of contractso n the line, they probably would have behaved "morally" (though the factors weighted in the decision process probably would have negated some of the morality). But they basically made a bet-- that the risk of the coverup was better than the risk of almost certain repercussions if it had leaked out. Esecially since it had been going on before anyone found out. They'd still have to deal with the fact that they didn't know... They probably saw coming clean and doing the right thing as a financial lose/lose, but the other had the reward of a huge continued payout from media, junk, etc... but with the risk of this.
I honestly think it was money, is what I'm saying. Money and reasoning like robots.
Oh, and I don't think that morality has changed, just the financial stakes. There always will be and have been people who WOULD have made the right call no matter hte financial stakes, but those people tend to not find themselves in positions of power.