Massive re-alignment has really been in play since the collapse of the SWC..
I'm not sure how much of that is on ESPN or just television money in general, with all major networks contributing (ND can stay independent due to their NBC money).
The 1984 court case is what really allowed it to happen. The schools formed an association (CFA) to negotiate TV rights for them, so there wasn't a realignment rush THEN. But when Notre Dame pulled out of the CFA to sign their first NBC contract, the schools realized their CONFERENCE should sell bundled TV rights for all their home games... The SEC noticed a rule that if you had 12 football members, you could have divisions and play a championship game, which was a huge draw to TV networks. So the SEC expanded to 12... and THAT is what turned conferences from "regional groups of peer institutions" into TV inventory cartels.
Of course it's "television money in general" but this was happening in the 1990s, when "sports on TV" was FIVE networks, and 60% of them were one company: ESPN?ESPN2/ABC; and CBS and NBC. CBS (12) and NBC (1) had 13 teams. ESPN had... EVERYONE BUT Notre Dame home football and the SEC game of the week.
Pretty sure ESPN hated the death of the Big East since that was a premier college basketball tournament for it the time (when the ACC poached the Big East again in the 2010's to get two powerhouse basketball programs in Syracuse and Louisville).
Every conference move being made, the conferences are consulting with ESPN on what it does to their TV deal. ESPN is most definitely BEHIND most the conference realignment moves. They're consolidating inventory.
Before 2003, they WERE paying three big contracts to the ACC, Big East and C-USA (since C-USA basketball also had major metro areas and powerhouse programs Cincinnati, Louisville and Memphis).
2003: ACC 9 teams, Big East 14, C-USA 15. (40 total)
2014: ACC 15 teams, American 13 (27 total)
They lost four schools to B10/B12 expansion (who they also had TV deals with), replaced Charlotte, Southern Miss and UAB with SMU, UCF and Tulsa; and they just stopped paying the Catholic 7, who don't play football.
Massive consolidation of inventory, and eliminated a payment to C-USA. If you REALLY want to see ESPN's chicanery, the Texas/Oklahoma and American vs Big 12 episode shows it off nicely. ESPN tried to get the Big 12 to collapse to void the $1.6 billion they owed them for four UT/OU lame duck seasons.