I mostly play pve, and solo content. I want to do every quest of every zone of the game.
I've been playing on and off for a few years, and by now I've done every quest for the main story AND side quest (delves included) of ALL vanilla zones, vyanderfell, summerset, thieves guild, orsinium, half of gold coast and murkmire, and starting elsweyr now.
For all of that I'm still only at cp 360 or so.
Now, I'm in no hurry to level up fast or anything but I would think that after all of that content I should be more than enough to have the full cp IMO. I recently beat the 1000 quests achievement too.
I know that group content and other things give better exp, but I prefer to solo and, like o said I'm I'm no need to hurry at all. I like to take things slowly and enjoy the quests, but I'm curious on why it gives so little exp compared to other means.