“If anything, a new member of the Big 10 will come from the Big 12; Missouri, possibly.”
If I had a choice in the matter, I’d remove Penn State and admit Iowa State to the Big Ten. I’d even be OK with adding Notre Dame - although the Fighting irish would proabably prefer to remain Independent.
Geographically, it makes more sense to have ISU in the Big Ten that it does for PSU. The Nittany Lions should ideally be in the Big East.
You've got it backwards. The idea is to expand the conference geographically so it gets more media attention in markets that currently ignore the Big Ten. ISU isn't going to generate any more revenue for the Big Ten if it joined.
Years ago with Joe Paterno was doubling as A-D, he attempted to build an eastern football conference but he couldn't make the other schools, principally Pitt & Syracuse, see the wisdom of it. So PSU goes the Big Ten route and later on the Big East expands to include football. Probably the biggest professional failure in Joe Paterno's career.
I don't see any way that Penn State voluntarily leaves the Big Ten. Given that the Big Ten is likely to expand eastward, there isn't much chance that the Big Ten will dis-invite the Nittany Lions, either.