These people may be geniuses, but how do they get behind the notion that a completely uninhabitable planet is our 'relief valve' for mankind if something happens on Earth?
One 'tech' failure and you're toast, literally (because no, not everyone can 'science the *beep* out of this').
MAGA!
Well the bigger the facility and the more manufacturing you can do there the bigger the chances for self-sustainability. Even if air and water is limited everything can be recycled if you have the knowledge, equipment and energy to do so.
Although the biggest danger to extinction is a bad AI singularity and mars wouldn't protect us from a superintelligent computer that wants to convert all resources in the universe into US currency for his shareholders.