| We're trying. I think these things are path dependent. There's not a particularly good, short-term, economic reason to go to Mars and build it up enough to be self-sustaining. However long term, it probably does improve our civilization's and species' (and perhaps life's) chance at survival. Unfortunately, we're not terribly good at long-term decision making. It could very well be that there was a window when the hypothetical Venusian civilization had the capacity to leave en masse to Earth but by the time the matter had become pressing enough, it was too late. For instance, it could be that advanced geoengineering techniques were able to hold off the effects of warming for thousands or tens of thousands of years which reduced the urgency leaving Venus, but over time the cost to maintain such systems became much too expensive and then some crisis (global war?) destroyed the geoengineering scheme, quickly heating Venus and destroying the advanced technological civilization and/or putting it into terminal decline. Point is you have to do such things when you have the chance, not necessarily when it seems most pressing. As Randall Monroe has said, "The universe is probably littered with the one-planet graves of cultures which made the sensible economic decision that there's no good reason to go into space--each discovered, studied, and remembered by the ones who made the irrational decision."
https://xkcd.com/893/ We went to the Moon ~50 years ago and soon stopped. It was somewhat of a historical accident that we went at all. It's not obvious that we will return in the future (even those efforts to go to the Moon or Mars face voices calling on even private efforts to be stopped). The future has not been written, and we don't know that it'll end up in the positive direction. But we, today, have the power to try. |