There is a big difference between a scientific mission and a self sustaining presence.

The later is still so far off that, as was said, other technological "paths" are decades, if not centuries, closer. If we survive on Earth that long.

What I am getting at is that viewing Mars colonization as a means to preserve human life is absolutely nuts. It's literally impossible in a reasonable timeframe, even with speculative technology/engineering, without changing humanity to the point that the whole fantasy changes anyway.