Living in Mars is not “life”, it will be little more than a constant struggle for minimal existence. Few people would want this meager existance or will tolerate it for very long. Imagine building a structure 20 feet underwater at one of the poles, it is like that - only more difficult. Fatal cold everywhere, no air, no heat. Existence, not life.

The second issue is that any attempt at a significant number of people on Mars would be a horrible drain on the limited resources of Earth for the foreseeable future. I doubt that many people on Earth will be willing to sacrifice so people on another planet can suffer daily. I don’t see people being anxious to sacrifice $10,000 to get $5 worth of food to Mars, especially when $6 can get that same food to someone needing it on Earth.

Some will claim that having people on more than one planet is “essential for continued Human existence”. Mars will not be self-sufficient for centuries and there is a good chance it will never be self-sufficient and never have enough spare resources to come to the aid of Earth after some planet devastating event meaning Mars would not be a “lifeboat” for Humanity, but rather the last part of the ship to sink beneath the waves making for a slow and painful end to Humanity.