You also underestimate the power of the human species when it comes
to self-preservation.

Humans will choose life over suicide if there are options to problems. That
includes living in space and on other worlds.

I also predict whether anyone likes it or not, once we actually get a
real foothold in the Final Frontier (assuming private industry gets its
act together for starters), plenty of disenfranchised groups of humans
will flee for the outer regions of the Sol system and beyond.

Some groups will fail, some will prosper, and some will probably come in
contact with other intelligences who may also be running away from the
conditions at home.

That's what life does best: Moves on when the place it is in is no
longer favorable to its survival. Space will not stop this, nor will life
stop and check its behavior along the way.