1. UT wields a ton of influence over the B12. They won't get that anywhere else.
2. UT has their LHN. They won't be allowed to have this anywhere else.
3. UT and OU have a symbiotic relationship. One is not as good without the other.
4. Money. They both make good conference money AND tier 3 rights money. They have to give that up in other conferences.
5. OU and OSU. The OK political environment has stated that if OU leaves...OSU has to go with it. Whatever conference OU leaves for would have to also take OSU with it.
6. TX politics. If UT leaves, the TX politicians will lose power that they've been able influence things in the conference. Will political leaders allow UT to leave behind all of the other TX schools?

OU has less of a reason to stay than UT does. So the only way anything happens is if OU leaves first.