Elon has detailed his plan for Mars colonization.
Colonizing and even Terraforming Mars is no longer science fiction.
Do we colonize Antarctica? No, it's too difficult and expensive.
Do we terraform Sahara? No, it's too difficult and expensive.
Mars Colonizing and Terraforming will be much more difficult and expensive than Antarctica or Sahara. So it's a dream at that time. We only can build a few scientific outposts for 1 - 3 trillion dollars.