The possibility of more than a handful of humans, if any, ever residing on Mars or anywhere in outer space are zero. Pronouncements to the contrary irresponsibly create false hope and subconsciousy or otherwise are designed to obviate the need to fix the awful mess that humans have created on Earth.
The technical challenges are too great, the atmospheres too hostile and the distances too monstrous to allow any human being to travel very far from the Earth. The concept of migrations or colonizations of massive numbers of people is ludicrous. Should it ever become possible, it will be far too late to save our home planet. In any event, how do you feel about leaving behind a trashed out garbage dump?
More importantly, there is nothing in space that is worth anything in terms meaningful to human existence. Minerals and metals do exist, but we already have the same in abundance. There is no water, there is no air, there is no vegetation, there is no warmth, there are no animals. There are only conditions violently hostile to human habitation. Other than the thrill of travel and the opportunity to take some fancy pictures, what else is there?
Scientific spin offs from space travel do produce benefits. But they should not be confused with the illusion that human life can exist in space in meaningful numbers.
These concepts must be separated.
Humans have brought the Earth very close to the point of landfill status. The causes are complex and inter related , but the monster explanation is virulent overpopulation due to out of control human reproduction. There is almost no ecological predicament, as well as a host of other societal problems, that would not be solved by having an earth population of 4 billion rather than the current 8 billion. Contributing causes to the witches’brew are unmodulated capitalism and endless, ceaseless habitat destruction.
Humans have been given a paradise, a true blue green wonderland. The objective should be to rescue what we have before moving on to defile new worlds. There are very powerful organizational interests who endlessly promote the illusion of humans living in space. Their motive is cynical: to continue doing things as they are.