Almost certainly they would, and there might be some small banks out there they could buy or merge with. That would get them out of a lot of legal issues, and also buy them some relevant legal expertise.

However, I seem to recall WalMart investigating this option a while back, and it never happened. It may be that the more you look at the option of becoming a bank, the more it looks like it would take over your life/business. Also, there are doubtless many lobbyists who the existing banks employ who would try to stop it.