And then as you look at the loot you obtain, you laugh at it being i70 since you already have the i90 Primal staff, drop it, and never do the content again.
My point here being that unless there is something that's actually worthwhile that drops from these monsters, they'll go largely ignored just like the current FATE bosses. People did King Behemoth for years because it had such a minuscule chance to drop an item that was damn near impossible to replace.
SE can create all the open world content in the world, but if there's no incentive to do it more than once, who cares?