What makes Mars beguiling to space settlers is not its current state, but its potential. On Mars, you have, at the level of chemistry, most of the stuff you need to stay forever. And the most basic stuff like carbon, oxygen, and water is easy to acquire, at least by the stingy standards of space. Mars is thus a place we can not only survive on, but expand into. With enough time and effort, Mars at least holds out the possibility of a second independent home for humanity.
