It was more nuanced than just BYU is religious*, but even if we choose to believe that's why BYU didn't get it, Utah certainly wouldn't have gotten in if it was the same team from under McBride. Maybe the Pac10 doesn't expand, maybe they grab a different candidate, but without Urban and Whitt, Utah isn't in the PAC12.
Which, you probably missed a few of the stronger candidates in San Diego St and and UNLV (both of whom had been pretty good at times, but more importantly would bring a major market and useful geography). I think those two and Colo State would have been the top options (assuming BYU/Utah were out and that they couldn't poach from Big 12), or just no expansion.
*thought about going into some of the other reasons that played into it, but ultimately it doesn't matter. This isn't about BYU and why the PAC12 didn't choose them. It's to say, that whatever the reason Utah had the chance (Texas declining or BYU being shunned or whatever), they were in position to take advantage and get the invite, and absolutely wouldn't have been without Urban Meyer. That hire changed the trajectory for the Utah program.
And other schools want to hire someone who can change the trajectory of their program and provide a significant boost, so they take big risks on unproven options.