to stay at 10.
I think during the process they learned there is a big media deal available to a P5 conference with 16 teams. Maybe from Netflix? Maybe a separate network? I think they realized that sooner than later they want to be in a 16 team league.
I know they've talked with other P5 schools. I'd bet that those schools expressed some interest in the B12 should a huge media deal be part of the calculus. And if the teams won't come to the Big 12 my guess is that the top tier teams in the B12 realize they'll want to leave to join a 16 team league somewhere.