In college football, you live and die by your ranking.
Thus, the perception of how good your team is, is more important than how good your team actually is. If at the end of the year, you are not perceived to be one of the two best teams in the country the chances of you becoming champion are very slim to none. Bowl subdivision college football is the only sport that has this phenomenon and the reason is that no other sport relies on rankings the way college football does.
Let's first take a look at rankings in other sports first starting with the pros. First of all, no pro league that I know of has rankings. Yes there are power rankings and polls that media outlets publish but they do not mean anything to what happens on the field.