ESPN is in a difficult position. Its revenues are actually dropping. This article explains why (and why revenues will likely continue to drop):
ESPN Lost 7M Subscribers
ESPN would love to simply pay less to the P5 conferences at the next renewals. But ESPN is still in a competitive environment, and will desperately need to hold onto control of all of the major conferences, including the B1G - which has a renewal coming up. The B1G wants much more $$, and FOX and NBC are lurking.
The answer is consolidation. The only way that it can continue to pay the conferences at least the same money without losing margin will be to move the BIGXII's most valuable properties into other conferences. In that way, they can pay more to the 4 surviving conferences and, more importantly, pay at least as much or more on a per-team-basis.
I see ESPN trying to force Texas and Oklahoma into the PAC, SEC or B1G.
Importantly, this will not be part of some grand scheme to get to four 16-team super conferences. ESPN couldn't care less about that - and forcing what will be the P4 to take the remains of the BIGXII and AAC will be viewed by them as more mouths to feed.
The ACC could also be the victim of the same orchestration, but the BIGXII seems weaker.