I agree that a (human) extinction level event is unlikely on Earth. However, from my perspective, the surivale benifits of moving to another planet is more to p

I agree that a (human) extinction level event is unlikely on Earth. However, from my perspective, the surivale benifits of moving to another planet is more to protect us from sudden unforeseen changes. Even if Earth is still more habitable then, say, Mars, we would have already set up and been using the infrastructure on Mars needed to survive, whereas our current life on Earth is much more dependent on planet supplied infastructure, which is at liberty to change suddenly. The other benifit is that we can take lessons and technologies applied to living off world, and apply it on world.