I never said they shouldn't or won't go into other mythologies, I Just said there's enough for one last game. Whether that means it leads into Egypt, for instance, or not. No clue.
If they go into other mythologies I think they'll continue the franchise beyond one more title. If only one more God of War game, period, is what you're talking about. Hell, for a while there I thought God of War was done but here we are.