The answer to that question is, of course, never. But just a day after Navy gave up their 130+ years of independence to join the Big East, the Big 12 decided that "Hey, we might want to actually have 12 members".
Further Big 12 expansion is "very possible," two high-ranking sources told The Chronicle. An expansion committee, dormant for months after the conference accepted West Virginia and TCU into league play, will meet today to discuss its options.
While conference officials stressed that no decision is imminent–and there is some opposition to moving beyond the current 10 member institutions–two schools are at the top of the list, should the league make a move.
Louisville, which the Big 12 considered adding last year, is the likeliest choice, according to people with knowledge of the talks. And Brigham Young, another university the conference has considered, continues to be a possible target. One official said the league was open to adding just one institution. "The Big Ten made 11 work for a number of years," the source told The Chronicle.
Obviously, this is still in the preliminary stages. But if you remember correctly, both Louisville and BYU were considered top choices to join the Big 12 in October when the conference added TCU and West Virginia. Louisville nearly got in over West Virginia (that was a fun three days for WVU fans), but alas, the Mountaineers managed to get out of the dumpster fire that is the Big East. But fret not, Louisville. You may be joining them soon. Unfortunately, 27 months would place the Cardinals at the same time that Pitt, Syracuse, and West Virginia are also "supposed" to leave.
This doesn't really impact Pitt, but if Louisville is also vying to get out of the conference (and let's be real, outside of the new members, basketball schools, and South Florida, who isn't), it doesn't spell good news for the Big East. I don't think, though, that an expanding Big 12 will cause other conferences to make moves as well. But for every member trying to get out of the Big East, it's another school that the Big East has to replace and at some point, the conference really is going to become a glorified C-USA.
Perhaps Pitt can use a departing Louisville to get out in 2013, but I don't see it. Part of the reason West Virginia may or may not get out in 2012 is because the Big 12 requires ten members for the TV deal. Not only that, but I fully expect Pitt and Syracuse to use a departing West Virginia to get to the ACC in 2013 regardless. If the Big East allows West Virginia to leave in 2012, but won't let Pitt and Syracuse leave in 2013, you can probably go ahead and cue the lawsuits.