In MMOs, you shouldn't necessarily be a hero. That is, the devs shouldn't necessarily make every character the players create be the same/similar hero. Just a person who gets stronger, helps people (NPCs) by doing favors to them (quests), etc. NOT make a story for himself which is exactly the same for thousands of other people because it definitely breaks the in-universe logic and I don't get how you can't find sense in that. Though you can make story (not a scripted one, just something to remember) with other characters, raids, PVP, etc. Of course, since there are many (if not most) people who disregard this and rather enjoy the story they're given, the devs won't ever "change the plan".
My problem is that you say that the "in-universe logic" argument doesn't make sense. Why? It's like saying that there's no "in-universe" at all. Unless you mean to say that in MMO's in-universe, different people can make similar story (even with the same timeline, sometimes) because it doesn't have to follow real world's logic AT ALL. I'd accept that as an argument, just that it's never suggested/implied to be the case.
This is getting old, though. Can we agree to disagree?