protected Earth-based shelters than space colonization.

Additionally I think that a rational person should have some survivalist skills in their arsenal to improve their/family/community chances in a major local or "small" earth-scale disruption.

I think building earth-based shelters is a good idea in general, but will run into huge psychological walls because there will not be enough shelter for everybody.

One advantage of the space strategy is skirting these issues, since space programs are not ostensibly survivalist-oriented.