Deathbed is a bit extreme. The Mountain West only dies if there's a reverse-merger. There's multiple FCS programs in its footprint that are of a similar quality as the FBS ones they struck out going after. There'd be an immense amount of pride swallowing for it to happen, but if it's death or paying a few million of those exit fees to bring the Montana programs up that shouldn't be a difficult decision.
Hell, the timing has never been better for Idaho to finally get that Mountain West invite they wanted so badly before being forced to drop back down. It won't happen, but Idaho athletics is in a far better place now than it's been in in decades (including beating a Mountain West team this season). Point is that there are options, even if they aren't in the FBS today.
A not small part of me would get a giant kick out of the Mountain West effectively ending up replacing what the old WAC was.