How many tons would you need to get out of the gravity well before you had enough orbital manufacturing capacity to begin building that sort of thing? I mean, I love the dream, but I don't know how you can make it a reality.
In the video Elon makes an estimate of a million tons to Mars (if I remember correctly) in order to establish an entirely self-sufficient colony there. Building orbital manufacturing would be a different kind of problem, but in some respects it's kind of similar. I suspect it'll make sense to establish a foothold on Mars first (which has a lot of necessary resources and less gravity means you can transition from the planet to orbit much more cheaply) and then maybe use Phobos and/or Deimos as manufacturing hubs for space-based hardware like habitats. Or maybe it makes sense in the short term (before Mars has the necessary infrastructure for big projects) to do manufacturing on the moon.
