I think he has too much time invested into TNA, and right now with the WWE/TNA lawsuit WWE has said that they will not work with anyone that was working with TNA when the lawsuit was filed until they settle it. Which is the main reason Flair hasn't been back to WWE yet, there have been rumors about when and where he will return but it is all speculation. Also TNA could really compete with WWE if they wanted to, but all their problems are about who is running the company, they have plenty of money but just don't know how to use it