Different Bowls are tied to conferences .... so on any given year, the Big Ten might be tied to the Rose Bowl, of NOT if the Rose Bowl is one of the Semi Finals ...

So SURE, there are more or less At-Large bids ... but on the years there are LOTS of at large bids, several of the Big P5 conferences don't have tie-ins, so they are At-Larges as well... so more teams are vying for the spot!