The only thing that kind of annoys me in the back of my mind, is that these guys are aiming to save humanity, but the average Facebook engineer figuring out how exploit users better is probably being paid 2-3x as much as the average SpaceX aerospace engineer. But that's what the free market is rewarding right now.
Save humanity? From what global warming? Global warming is nothing compared to Mars. If we can terraform mars into a beautiful landscape then climate change isn't really an issue on earth...
Going to Mars for scientific research would be an incredible step forward for man kind. But the feasibility of space still holds a lot in question. It is exciting, but let's not call it "saving humanity".
Save humanity from an extinction level event. Think asteroid impact or global nuclear war rather than climate change. Musk has been pretty explicit about his intention to make humanity a multi-planetary species. [0]
What nightski is saying is that achieving a truly independent colony on Mars, which can survive the destruction of Earth, is much harder than just putting people there.
Mars might an interesting playground for testing climate engineering, since it'd be hard to mess it up more than it is now. That said though, it's hard to imagine fixing things like the lack of atmosphere without a lot of investment.
While I agree that less effort should be spent on what Facebook wants to achieve, there are way more engineers that would rather work on space stuff than positions so of course they are going to pay less. So the market is functioning as it should.