If I understand the math correctly, this essentially values Big 10 teams programs at an average of 2 billion each? That part doesn't make sense. The financials aside though, there's another huge potential complication here.
I think this could really complicate future expansion for the conference. First off, the private equity investor is not going to want to have their share diluted. So, they're going to want to own 5% no matter if there's 18 other programs or 30 other programs. This would become a bigger deal the more programs join, as the piece of the pie shrink even further.
On the other end, most major programs are not going to want to join a conference where the other teams have that 100 million windfall advantage over them while their piece of the pie remains 95% of what it otherwise would be.
Also, the 100 million isn't really as big a deal as it sounds like at first glance, at least not for a major program. Alabama football alone makes more than that in one year, so if a program is desperate it's a big deal but otherwise it's basically a coaches buyout or something.