That's a good question. If traffic starts to pick up and the economy started to improve, I could see them trying to do that. They've been doing the same thing at RDU for years now.
Remember, AA basically closed it's hub at RDU in 1995, but they still hold a long-term lease on Terminal C, which I believe has 26 gates. The RDU Airport Authority has been trying to get AA to give up some of those gates, but AA has refused (so far). Their strategy has been to hog all those gates so that there was very little room at RDU for other airlines to come in and compete with them.
Up until Midway ceased operations, AA was subleasing 17 of those gates to Midway, but with Midway out of the picture it seems ridiculous for AA to keep all 26 based on their current operations out of RDU, especially since they are trying to save every dollar they can right now. Still, I wouldn't put it past them.
BTW, I love TxAg's idea about WN operating out of DFW, and that's something the citizens of Ft. Worth probably would support, whereas Ft. Worth has not been supportive of lifting the restrictios over at Love Field.