Endgame has always been what mattered in MMOs since there's very little to do beforehand except for grinding, crafting, and the occasional quest and storyline mission.

It's been this way in FFXI, it's been this way in WoW, it's been this way in Aion, it's been this way in Everquest, it's been this way in them all.

The reason for this is actually incredibly simple: The majority of your time in the game will actually be at max level. So the more endgame content there is, the more likely you'll stay and keep playing.