Lizard said:You can always grind AA until they raise the level cap.
Seriously, I would be VERY surprised if there isn't a 'divine' or 'immortal' tier planned for PHB 2, or PHB 3 at the latest. One of the points of fixing "the math" was to make the game playable across all levels, and the high level monsters we've seen have roughly the same number of combat options as the low level ones.
As gods are level 37 solo monsters (apparently) I don't think this will be the case.
Besides, what would be the BBEG at level 40?........