Would OU ever make a move without Texas? If not, isn't that sort of lame? Put on your big-boy pants.
I posted earlier that I didn't understand your post. Somehow, I missed the "If not" part of it.
So, to answer your questions . . . .
I think that the OU administration views the annual series with Texas, at the Cotton Bowl, in Fair Park, at the time of the Texas State Fair, as a cornerstone of OU football.
As a result of that thinking, OU would have to think very long and very hard before doing anything to jeopardize that game. Although that game existed for almost a century, and for 66 years as a game played annually in Dallas, before the formation of the Big 12, it is not at all certain that it would continue if either OU or Texas were to leave the Big 12 without the other. We can see what happened to the annual Texas-Texas A&M game when the Aggies left for the SEC.
Are there OU fans who believe that OU should not feel bound to automatically stay linked with Texas, even if it meant risking the RRS? Yes, there are. I am one of them, even though I believe the RRS to be the equal of any CFB rivalry game except for--maybe--the Army-Navy game. Having the flagship school of the second-largest-and-most-populous state in the Union running your conference is not all fun and games.
But I can't think of any currently likely circumstances that would warrant such a separation. It would make no sense for OU to approach the Pac-12 as a solo act. I don't want to see OU in the SEC. And I don't see OU going to the Big Ten as a non-AAU member, the chances of becoming which our former school president probably queered for the foreseeable future by submitting false data to USN&WR about alumni endowments.
So, absent some irresistible, once-in-a-millennium opportunity, I imagine OU will stay tied to Texas for as long as Texas wants to be tied to OU.