You're not understanding. In the Big 12 Texas could be mediocre on the field and have their value still thrive because they're the conference's top traditional blueblood and biggest college football brand. Even with so-so W/L records, they're still the program everyone talks about in the Big 12.
In a superconference with the likes of Bama, tOSU, Georgia, Michigan, LSU, Oklahoma, ND, USC, PSU, etc., if Texas turns in consistent .500 seasons, their value will not thrive. They will not be the program people are talking about. Their brand will take a major hit. Sure Texas fans will keep watching them. But the rest of the country will stop caring about them fast because they'll be in a conference with at least a half-dozen programs with equal or better brands that are winning.