Once mars settlement gets going, the moons of mars Phobos and Deimos also make for attractive targets. It might be that once starship works, we do all kinds of

Once mars settlement gets going, the moons of mars Phobos and Deimos also make for attractive targets. It might be that once starship works, we do all kinds of things, and it turns out that asteroids work better than planetary surfaces. So the belt becomes the focus of economic activity, and the mars colony is just a novelty kept alive by the Musk Foundation.