I tried the Oblivion remake and have been just assaulted by the number of things I can try and do. There's a story behind nearly every quest with some kind of ironic twist. Thinking of how you can get over the next hump by developing your character is fun.

Now, compare this with the newer Fallout 4, Outer Worlds or Starfield. There are a ton of fetch quests. There's nothing at stake seemingly in a lot of cases, or whatever you're trying to do seems really far off. Nothing is immediate and everything is impersonal. That's boring.

So to pose a theory, it's about the quests, not necessarily the world.