The preseason polls are as good as they can possibly be. Despite having an impossible job, they're a reasonable assessment of which teams should, based on talent, stay competitive.
But once the games are played, the polls will always, inevitably, prove incorrect and end up covered in red ink. And this year, despite just two Top 25 teams losing to unranked foes, was more of the same.
Other ranked teams lost to fellow ranked squads, which—fair or not—will consign them to a dip in (or completely out of) the rankings. And others, even in victory, looked bad enough to warrant the same fate.
All we know before the season is that we know nothing about the season. These teams are living proof.