New MMORPGs are accused of being rip-offs of WOW. Before that people compared MMOs to EverQuest. New MMOs always copy what they think is working and slap on a new theme and and tweak a few mechanics. We could say that the developers are greedy and want a piece of that WOW pie, but I hardly think that’s all there is to it.
I used to play Muds, and every mud I played was a rip-off of some other Mud. I don’t just mean they copied some game-mechanics or ideas about leveling, I mean they copied entire zones and sections of code. I played Vampire Wars, which was a rip-off of God Wars, which was an altered version of Merc, which was a modified version of DikuMud. I coded for Cythera, which was a split off from World of Carnage, which was a heavily modified version of CircleMud, which itself also derived from DikuMud.
To this day, slash commands like /bow from early Muds are still used in the most modern of MMOs. We still have hit points and mana points and we still work on getting better gear when we’re done with leveling. We still have these things because they work. Why fix what isn’t broken?