From what little I have heard from my semi-reliable source here in Austin, it is more likely that UTx was flattered, sweet-talked, pressured just a little bit, and UTx vanity appealed to by OU and the SEC front office.
OU apparently thinks they are in a jamb financially. Why (or why they got that way) I have no idea. Lots of O&G money in their fan base, and that money has kept their athletics, or at least their football, flush for several generations, but apparently OU was/is seriously looking around for more bucks.
OU, it is said, knocked on the SEC's door, and were told that the SEC would be more interested if OU was a package with UTx. UTx was approached with a promise of more money, sharing an exclusive top-conference billing in the State of Texas with A'nM, and (TAH-DA!!) a chance to do a big-time job sticking a finger in A'nM's eye. The Aggies had been promised, as they claimed, an exclusive in the State of Texas.
Apparently some that make a difference at UTx actually believe the "conference is holding us back" crap, too.
According to my source, OU is the tail and UTx is the dog, since the subject was brought up. Just like UTx has been in charge (with some interference from the Lege, to be avoided this time) since the gestation of what became the Big Twelve v1.0.
Having learned their lesson from being stuck with Baylor and TTech the last time they changed conferences, and with OU sweating only a little bit about political blowback leaving OkSU behind (and UTx wanting to ambush the Aggies, of course), all of the SEC office, OU, and UTx managed to keep a lid on the deal until it was a fait accompli.
I trust the source enough to repeat the story anonymously on this board, but that's about it.