People from the right cultures can adapt to live in crowded areas. The Japanese have done it, utilizing cultural values which Americans have usually regarded as humorous. I doubt if your Mark I American could do it. Too used to space, and where it's crowded act out through drugs, crime, violence.

Nobody said that space colonization was something reserved for Americans. If Japan ends up being at the forefront of humanity's spread through the galaxy, more power to them. In five thousand years, or even five hundred, what difference would it make? Heck, seventy thousand years ago we were all black.

I do think you're oversimplifying Americans. For one thing, which Americans are we talking about? I could look at a photo of any person on the planet, and he could easily be an American. Unless he was photographed standing out on the veldt dressed in a set of neck beads. Even then, maybe he's from Iowa and on vacation.

And it's amazing how little crime, as a percentage of population, there is in crowded cities.

Our ancestors weathered an Ice Age with almost no technology at all. Even a full-scale atomic exchange between the U.S.S.R. and the U.S. would have left large segments of the Earth almost free of fallout.

Humans--as a species--will do just fine given any conceivable disaster that would not also destroy any "shelter domes" or submarines. If Bronson Alpha comes rolling in, you'd better have some spaceships.