Because the end goal is to put teams in a spot where they can compete for a CFP bid. That means challenging non-conference games, and being able to lose without putting the NY6 bid at risk. Boise State was a very good team in 2006 (with a horrid conference schedule), but I think that BYU was better. But once BYU got that 2nd loss, there was no way BYU was going to end the season ranked higher than Boise.