Well technically it has been (even longer tbh), all of its basis was set up back then given that the thing that the game runs on and needs to actually work was created back then. Honestly though the entire point is that nothing rips anything off, if you think like that then technically bungie ripped off crysis with the invis and bow and arrow, cod with a wide selection of the guns, attachments, movement etc, borderlands with the art style and rpg elements, world of Warcraft with the raids. Every game has similarities to every game, it doesn't mean they are ripping each other off.