I think I know how OK State can get into the SEC.
Missouri would leave for the Big Ten, which would also add Iowa State to keep the membership even. This opens a slot for OK State in the SEC, and a slot in the Big 12 for a school other than Boise State, BYU, Houston, Memphis, SMU, South Florida, Temple, and UCF - all of whom I want to join the Big 12. Perhaps that 9th new member will be Colorado State to secure the Denver market. A tenth new member would also be required in the Big 12 - perhaps Tulane (ironically a former SEC school).
In terms of media rights, CBS and NBC would be very interested in having the Big 12 in their stables, perhaps even a joint deal. CBS would either partner with Turner for their half of the package, or put their cable games on Paramount Movie Network. NBC would use USA for the cable portion of their half of the package.
As it is, CBS is losing the SEC before OU and Texas join, two seasons shy of the partnership's 30th anniversary. The Big 12 would be easy to get. It's possible CBS could also get Big Ten football games in addition to basketball, but that is a tougher sell for that conference. If CBS does get Big Ten rights, they could very well insist on the Big Ten having night football games every week of the season, up through and including Thanksgiving weekend, where the Big Ten has never played at night unlike the other P5 leagues and unlike the similar footprint G5 league the MAC. This could open the door to Michigan-Ohio State being played at night.
As for NBC, they only have Notre Dame, which hasn't won a national title since 1988 - three years before that partnership began, and if ND is considered its own conference, it has the longest active title drought of all the collective P5 memberships, 16 years longer than the next drought that of the Pac-12, frustrating the network.
I considered NBC my favorite to pick up the OTA portion of the SEC package. I thought they should have the SEC considering ND's history of coming up short as an NBC property. In fact, they were eliminated from the CFP by the eventual champions, the SEC's Alabama, last year. And I thought it would have done NBC good to have broadcast rights to the conference with the most national titles in the 21st century.
I've said at times that NBC might dump the Irish if they don't win a national title by the time the current extension ends after the 2025 season. But would they actually do it if they had another conference to broadcast?
There has been talk about ND ending its football independence permanently, but I don't think that will happen. Their rivalry games with Navy, Stanford, and USC are too important, as well as the ability to schedule other top-flight programs more frequently than other P5 schools.