Depends on the timescale, and what other tech is the prerequisite to this and what other things can be done with that tech.

Even with cheap rockets, Musk was talking about 6-digit-dollars for becoming a Martian, I don't see more than a few million people wanting to spend that much for that outcome.

If we get self-replicating robots or whatever, big space stations aren't that expensive, but also Earth is huge and you can extract minerals from seawater electrolytically and PV is already cheap, so perhaps we'd just get a load of seasteads instead: https://en.wikipedia.org/wiki/Seasteading