From what I've read here, the original plan was that the SEC and UT/OU were going to stay quiet until 2022 and then announce it, probably around the same time that USC/UCLA to the Big 10 dropped.
If we don't find out you're leaving in 2021, the status quo maintains with Bowlsby, and the Big 12 gets the rug pulled out at the same time as the Pac 12 with an incompetent old world leader manning the ship.
Because that bomb got dropped on us '21, it forced us to take action, add schools, and ushered Bowlsby to the finish line while we started finding a better replacement. Meanwhile, the Pac sat around laughing, puffing their chest about the Alliance, and punting on an opportunity to add all those public schools with more passionate fanbases than what they had because of culture and politics. When the Pac got their rug pulled out last year, we had closed in on Yormark, added 4 schools, and had a pretty damn good TV deal in place before they had even figured out what happened.
If UT and OU leave in '22 with Bowlsby still in charge, the Big 12's a hell of a lot bigger mess. IMO.