Oh, my god. There's so much wrong with this article. Like, I don't want to get all "internet troll hyperbole" about it, but there is really a lot wrong with what's been established here, both in the article itself and in the comments.
First of all: It hasn't ALL been "done before". Humanity has not wrung out every single possible story option within the last 20 years. Creativity has not "died out", or stopped existing. The fact that Avatar rips off like five different movies is not an "inevitable result of human behavior" - it's lazy. The Na'vi are a transparent, 2d race of super-perfect Idolized Aborigines with cat-faces and ear spacers. That's not "inevitable". That's "James Cameron had a message to get across, and the message was: Natives are great". The fact that the military was comically evil and corrupt wasn't a result of "well, we've used up every other story possibility", it was a thin and eye-rolling way to make them the bad guys.
Imagine if it had been reversed. Imagine if the natives - you know, the hot, blue-skinned cat people that people jerk off over - had actually been the BAD GUYS, and the gung-ho marines had been the GOOD GUYS? Name me one movie like that. Imagine if the plot had been the same, but instead of being an idolized, super-sexy race of near-humans who love nature, the aliens had been a bunch of disgusting, fish-faced, fanged-maw freaks that the human protagonist falls in love with anyways. Imagine if the movie had been the same, except instead of the marines being comically, Snidely Whiplash evil, they'd been reasonably attempting to negotiate with the Na'vi and the bloodshed was a result of a misunderstanding instead of a need to make them an analogue to White People In Colonial Times.
None of these would sell well, of course. Avatar was a lengthy, drawn-out way to sell tickets with fancy CGI and manipulative design. But they would have been original, and different, and not ten thousand "white man goes out to commune with native race, turns out to be chosen one and falls in love with their princess" movies. Hell, it might have even challenged the genre or something, and I mean that never goes well with James Cameron. It's not like he made a movie that basically codified space marines in modern perception, nor did he make a movie where an evil robot assassin was turned into a sympathetic father figure. No, all that James Cameron has ever been good for, or will ever do, is "standard action schlock with no inventiveness or deviation". And what else should we expect? It's All Been Done Before.
