The thing about Avatar was, the primary purpose behind extracting the natural resource (the floating rock) was to take it to Earth as a new power supply. Yes the company doing the extraction was going to get rich in the process, but the people of Earth would also benefit. Earth was "dying," a new source of power was desperately needed.
I don't recall anyone actually saying 'Earth' in the introduction to Avatar. They probably did but I don't remember it.
I always thought the movie failed because large groups of intelligent humans just don't behave like that when money is the prime motivator.