There is no real end, because every major patch or expansion adds more quests, so it's pretty much something that will continue for the lifetime of the game.

I understand that people play for different reasons and not everybody likes questing and story, but a lot of content is gated behind it, so...

I guess some day when the main scenario has bloated to an extreme amount, they might need to open up content to people without going through it at the cost of the story making less sense?