ESPN and SEC can't even reach agreement on ESPN paying extra for a 9th conference game amongst the existing 16 SEC schools. Not sure if that is due to ESPN cash flow issues or SEC demanding more money than ESPN is willing to pay. So there is now no way the SEC expands in the foreseeable future.
I think that's because the SEC is purposefully asking for too much from ESPN for a 9th conference game. They know that their weak 4th non-conference game supports the allure that the SEC is the top conference due to their padded W record.