The saying goes that when the Brits were marking out Toronto the surveyor put a stake in the road and said, let’s 'ave a new road 'ere

I think you missed my point, I don’t believe we have a self sustaining population on earth (yet)

I don’t disagree that having a self sustaining population of humans somewhere other than earth will be an important milestone.

But a much more pressing milestone is a the first self sufficient population, which I don’t see mars supporting