Long-term stability is the biggest detriment to the Big XII. It's currently the OU-UT conference. If either Oklahoma or Texas bolts, there's nothing left but tinfoil and duct tape holding the conference together. The Big Ten, meanwhile, could stomach losing Ohio State, Michigan or Penn State -- maybe even two of them -- and still remain a strong conference.
That was a different story several years ago, but the Big XII ran off Nebraska, Colorado, Mizzou and A&M. They ran off FOUR of the top six teams in the conference. So they're left with the Sooner-Horn Two-Step and then a bunch of career underachievers like Kansas and Baylor. Whoopie.
To put it in perspective, imagine that the Big Ten scared off Penn State, Michigan State, Wisconsin, and Iowa. You're left with the entire conference hanging on Ohio State and Michigan for relevance, because let's face it, nobody really cares about the annual Rutgers-Illinois matchups.
Or picture the SEC runs off Georgia, Florida, LSU and Auburn. Gotta hope that annual Alabama-Tennessee game can pay the bills for the whole conference because nobody's getting rich off Kentucky-Ole Miss. Or if the Pac-12 ran off Washington, Oregon, USC and Arizona State. OOOOH BOY, I can't wait for that big Stanford-Oregon State game!!!!