Annnd UM is never moving to the FBS, and neither are the Puds. That is wishful thinking, or not. The state doesn't have the money to support the schools, and even if the money was there, it's Montana and while people may love the teams, they love their money more and no one is willing to pay more in taxes to support either school moving up. Because, really, that's what it comes down to, money.
I was born, raised and lived in Montana most of my life. I think I have a pretty good feel of what Montanans are like. You can hardly get a school bond passed to educate the kids, let alone try to get funding approved to pay for two Universities that at least half of the Montanans have little actual direct link to (to include the transplants) the universities.
It's fun/frustrating to speculate though.