NDSU already makes $500k a year off its media rights between TV and radio (that's more than any school in C-USA) and is competitive with P5 schools in the region for recruits. A kid whose best offers are a MAC school and NDSU is going to NDSU. Throw in the fact that they are financially stable and a poor geographic fit for any G5 conference, and they're pretty happy where they are.

JMU is different. Their athletic budget is in line with the likes of Memphis and USF. I don't think they have much to gain from a Sun Belt or C-USA invite, but if the American came looking for new membership on the East Coast, JMU has some cache and could possibly pull that off. But their football program also thrives on FBS transfers (like many at this level), so that would have to change if they expected to compete at the next level.

Overall, though, it's just not a good environment to move into right now for the schools winning at this level like those two are. You don't have access to a national title, your bowl payouts don't cover the budget increases unless you're in the American or the Mountain West, the Sun Belt isn't looking to expand, the MAC sold its soul to TV, and C-USA offers no revenues to speak of. It's not worth it to make the jump and sweat it out hoping a P5 conference raids the American.