The thing about the last five mass extinctions is they didn't involve a species so good at adapting the environment to serve its own needs that said species could colonize Mars.

Of those 5 mass extinctions, did any of them make Earth less habitable than Mars is today? I'm genuinely curious.

The Cretaceous–Paleogene extinction event is theorized to be a massive asteroid strike which "release[d] the equivalent energy of several million nuclear weapons detonating simultaneously" and killed off 75% of extant species.

Sure, the preppers will be gleefully LARPing Fallout from their bunkers, and a small percentage of humans would probably pull through. Maybe.

If we have a seed colony on Mars, it significantly de-risks human extinction from an asteroid strike. Elon is the ultimate prepper.