Huh? Sure we can prevent some cosmic events (asteroid redirect) and even mitigate others, by having backup of life elsewhere in the solar system. We have the technology, would you rather everything dies because of some ideal? Don’t let perfect be the enemy of the good.

As to your last points, that’s how it’s been done during the last few expansions. But spaceships are expensive - tonnage to mars is insanely expensive. The incentive is to get a return on your investment: a sustainable colony. Sure, the billionaires won’t be the first, but someone has to be. And what right do we have? It’s our imperative to ensure the continuation of life by spreading it through the cosmos. Anything less would betray our base genetic instincts.