Why did people want to escape Earth though? Maybe they felt Earth was past saving.

A lot of the old stuff isn't so much about escaping Earth, as outgrowing it. A feeling that it's our destiny to expand to the stars, just as it was life's destiny to come out of the oceans.

The more we look for alien civilizations and come up empty, the more I feel like they were on to something. For all we know, life is exceedingly rare in the universe.