Our corporate attorney has always told me that you don't want to be the one that looks like the bad guy if you go into litigation. Not exactly a deep legal analysis, but generally a pretty accurate one. The causative is a hurdle, but the biggest fact would be that the Big 12 schools had a contract that guaranteed them $200 million each over the next 10 years, and now they don't.
I think a very realistic outcome here is also that the Big 12 leftovers can't find a home. The Big East basketball schools went bananas last time the football schools proposed adding the Big 12 North, and I don't see much changing. I also see the football schools becoming less aggressive now because the huge Comcast deal is hanging out there for the league as it is currently structured. Why mess with a good thing? Missouri is a possibility to the SEC, but I think the SEC is more likely to look east than west for a 14th member, and I don't think it is a done deal that the SEC even goes to 14.
If the 5 Big 12 schools are stuck, they will have two assets: a BCS bid and a few decent programs. I think they do the same thing the Big East did in 2003, grab the best regional programs not in a BCS league, Boise and BYU, and build around it with whatever quality they can scrape together. I could see them adding Boise, BYU, Houston, SMU and Colorado State. That conference is a marginal BCS league, but with the threat of litigation hanging over the SEC, a relatively high quality of basketball enabling them to get a decent TV deal, and the reluctance of conference commissioners to start a stampede to superconferences, I could see that league surviving.