This is a limited line of thinking. Eventually humans who are capable of living in a self-sustained colony on Mars will also be able to live anywhere. In space

This is a limited line of thinking. Eventually humans who are capable of living in a self-sustained colony on Mars will also be able to live anywhere. In space using asteroidal/cometary resources, for example. On the moons of Jupiter and Saturn, etc. The jump between being able to live on Earth and then Mars is actually much greater than the jump between being able to live on Mars and anywhere. At that point humanity no longer would be planet bound. We'll be building cities that house billions of people in, say, the Earth-Sun L4/L5 lagrange points, or wherever we feel like it.