Interesting article (sorry if already posted) on how UT and Arkansas were supposed to join the SEC back in 1990, but TAMU got the Texas legislature to stop UT from going. Well, actually, the Texas legislature tried to force the SEC to take TAMU, but the SEC didn't want TAMU.
http://blog.al.com/press-register-sports/2010/04/finebaum_how_texas_nearly_join.html
If anyone, the SEC is responsible for the "destruction" (if you want to call it that) of both the SWC and Big 8. After the 1984 Supreme Court ruling against the NCAA regarding TV rights, the CFA TV deal negotiated back in 1981 was upheld, and the Big Ten and Pac-10 (both of whom did not join the CFA), signed lucrative independent network deals with ABC.
If you check out the history, the "experts" at that time (1984-1990) generally speculated that the SEC was the most valuable conference in the CFA, and that the SEC would do financially much better by getting their own contract (like the Big Ten and Pac-10). Conversely, they also speculated that if the SEC left the CFA, the CFA would have a very difficult time negotiating a comparable TV contract without the SEC, Big Ten, and Pac-10.
The 1990 SEC expansion pretty much confirmed that the SEC was setting up for an exit from the CFA. In 1991, Notre Dame left the CFA and got a big TV deal with NBC. The SWC and Big 8 saw the writing on the wall that they were going to be left out financially if things remained as is, which at some point precipitated the negotiations to merge the two conferences. Ultimately, the SEC did leave the CFA in 1994, and got what at that time was an enormous TV contract.
Since the 1980's, conference realignment has always been about money.