> we’re forced to keep all the eggs of humanity in the single basket that is Earth.

Sadly, this will be true for thousands of years, and quite likely forever, because we only have a couple of generations before degrading environmental and conditions on Earth make us poor as a species and rob us forever of the stars.

Mars is the only possibly habitable planet, but terraforming it would take generations, performing a feat of civil engineering literally orders of magnitude beyond anything humanity has attempted, repeating it each year and still ending up with an average temperature of about -40ºC, up from today -60ºC, but still not comfortable in the slightest.

And the idea of conveying 80 million people off the planet every year - what would be needed just to get rid of the yearly increase - is ludicrously unrealistic given than less than 600 people have gone to space in the 60 years since it started, not one permanently.