Yeah. I don't think another publisher would take up the MLB mantle for 2013. If 2K is out then I wouldn't expect to see anything until the next generation of console launch. I am sure there would be some interest in doing arcade junk with the MLB license but nobody is going to get serious with it until next gen, if ever.
I don't blame 2K - I blame the MLB for watching their sport die and not trying to do a damn thing to save it.