You guys do realise there is a difference between copying and getting inspiration from something.
I mean most movies are just copies of eachother (ever tried watching Avatar and Pocahantas back to back ? SAME FRIGGIN story, Avatar imo is still a good movie but that's OT)
You can't just INVENT something completly new otherwise it will be too offputting. I mean you could create an MMO where you gain lvls by doing a garbage route (no offense to people who actually do that as a job though), is it a new idea ? YES, would people play it ? Not so much I would think.
When it comes to developping new games the companies need to stick to something gamers can relate too. Everyone want's to be some form of knight in shiny armor, or a powerful mage or a vicious rogue or whatever. The whole point is to be able to enjoy yourself whilst playing an avatar who isn't real nor based on any real stuff (too some extent).