I don't know what it would take to be self-sufficient but neither do you. Eventually humans will have to have a sustainable presence off Earth if we don't want our species to go extinct. Why can't somebody give it a try? Maybe we don't quite have the technology for it yet but it doesn't hurt to have a good go at it. Extinction would be a real tragedy because we might be the only hope of intelligent life in the whole universe ever. It's incredible how not a single other species we know of even comes close despite millions of years of evolution.