Utah would have been forced to start at square 1 with someone likely from the outside that did not understand the Utah dynamics, and the chances of striking gold twice with another Urban Meyer were slim (especially since the new coach wouldn't be able to lean on KW like UM did). It would have sent a very clear reinforcing message that BYU is top dog in the state - otherwise, Kyle would have stayed at Utah, his leaving would clearly mean BYU is a superior job.

On the other hand, I don't really think Kyle would have done any better than Bronco at BYU. 2005 would have been a transition year with a 2nd place finish in conference, 2006 & 20007 were championship years, and in 2009 & 2010 KW would have still conceded the title to Gary Patterson.

You could make the argument that if Utah plummeted after KW's departure, there would have been no 2008 BCS and no PAC12 invite. Truth is probably yes to the former, but no to the latter. The PAC12 still would have passed up BYU, even for a weaker Utah (heck, they took Colorado didn't they?).