Not ruffling any feathers, giving my opinion which is well based. The Big 10 has no where to go to expand, the 4 available ACC schools that are AAU members, a Big 10 requirement for any school but ND, Duke, UNC, Virginia, GT, have already turned the Big 10 down. That is why the Big 10 ended up with Maryland, the last available AAU school.
ACC schools will not leave the ACC for the Big 12, or any other conference. The ACC is solidly together, especially with ND coming in.
The Big 12 has stated they will not expand if it causes the current 10 to make less money. Neither UC or UConn raise the Big 12 TV rights by $25 million each. The only schools that come close to raising the TV rights $25 million each are schools such as Florida State and Miami and neither has any interest in joining the Big 12.
With the Big 10 and Big 12 unable to make moves realignment within the Power 5 is for all intents and purposes over.