This.

Something that gnaws at the back of my mind is that the survival of our species is contingent on absolutely nothing catastrophic happening to the single planet we inhabit. All of our eggs are in one basket, so to speak.

Until we have a viable network of colonies offworld, we will continue to have this problem.

Absolutely. Ultimately we must leave this place. Not now—and certainly not in the near future—but eventually "we" (or whatever we become) will have to leave this place in order to ensure the survival of our descendants.