I wrote a long essay about this that I have yet to publish, but my basic point is this:
1. Mars is a fucking desert. There is no air, water or life.
2. Venus is covered in CO2 clouds and sulfuric acid rain. Metal melts on its surface.
We are not going to live in space. To even WANT to live in space is an absurd fantasy that is in violent conflict with the reality of space as an airless, inhospitable, largely resourceless wasteland that requires enormous effort to travel through and survive in.
Why, then, does Musk insist we need to live in space? I think this is simply an update of our previous desire for an afterlife or a heaven. Since we are no longer willing to fantasize and organize around the Kingdom of Heaven, we've turned space into the Kingdom of Heaven, despite the fact that it has very few actual heavenly qualities.