The teams that the BIG and ACC want are already in other conferences beside the Big 12. They can't raid the SEC, but the BIG can still raid the top of the Pac and the ACC still has a chance with Notre Dame that they are likely to keep open forever. Incidentally, the BIG could raid the ACC again as well.
It seems that the BIG has the next move, and it will be interesting to see if they mess it up like they did with Maryland and Rutgers.