I don't fully agree, you're hinting at WoW and how simple it is (if I read your post right).
Yet in order to see the lore and what not you need to raid. Even in WoW raids get balanced around "good" builds (because the beta-testers are hardcore raiders).
Sure plenty of people didn't need a raid-build to enjoy WoW, but those people didn't have the goal to learn why you're fighting Algalon and who exactly that is.
If you want to know what's up with Algalon you buckle up and get a decent build (or wait until you out gear the content).
Also the market is a lot more open now than when it was just GW vs WoW vs Eve vs ...
People got tired of WoW and are looking for other stuff, so they try out other stuff making other stuff more successful. I'm 100% certain that if GW was released now (with upgraded GFX and jumping since that's apparently a deal breaker for people) it would be more successful than it was.