>The most effective answer is distance. While unlucky mobs can walk to your solar panels in the desert after civilization breaks down, how are they going to get to Mars? Get a good trampoline to jump on?
On some Mars colony with the foreseeable level of technology for the next 100-200 years you're even more prone to death and to worse climate than whatever might happen here on earth.
Beyond 200 years, Elon Musk could not care less about...
On what evidence do you think that Elon Musk doesn't care about the future beyond 200 years?
I believe that he wants to go down in history. And he wants there to be a history for him to go down in. True, he won't be there for that. But the thought of what it might be is a positive motivation for him.
On some Mars colony with the foreseeable level of technology for the next 100-200 years you're even more prone to death and to worse climate than whatever might happen here on earth.
Beyond 200 years, Elon Musk could not care less about...