Maybe he just left... and went home? Why does he need to stay in Eorzea?

If somehow we can defeat Bahamut in the new version it will be disappointing (For me at least.) How that if at most an alliance of 24 players could defeat the Wyrm king after he had destroyed everything. I am hoping that Bahamut casted his Mega Flare attack, left the area, and all that we are stuck with is the Garlean Empire. That is who the real enemy is.