Yep. The list of things that could make Earth a worse place to live than Mars is very short. A big enough asteroid to liquefy the entire crust would do it, for a while. A "mere" dinosaur-killer wouldn't be enough. Nor would nuclear war. Most of the rest of the options are still sci-fi, like Grey Goo events, or a very contagious very deadly infectious disease (and that would have to have some way of sticking around for a long time, for an orbital habitat or sealed earthbound habitat not to still be better than Mars, since you could get back more easily once it was gone or we had a way to fight it).

Otherwise you've gotta start stacking disasters to get close, and even then it's pretty difficult. Mars is really bad.

Just look at decadence in rather inhospitable environments on earth... Let's take Dupai or some deserts in USA with golf courses. No way whole Earth will get worse than that. And basically we already have luxury lifes in such places, air conditioned malls, apartments, cars. Over use of water to water lawns...

Also, it is not like you couldn't vastly more cheaply and easily build Mars bunker on Earth. As we are centuries away from planet scale geo-engineering.

Agreed, I think another thing missed by so many is that if we can settle mars that same technology can be used here on earth to make inhospitable parts of the planet usable again should we mess it up badly enough.

Yes I know that. But do THEY know that? I’m not so sure. Elon/Bezos seem to think you can hand wave/buy the radiation away like they do their problems on earth. Maybe with absolutely massive amounts of money they could find a way. And we would be the ones footing the bill for that.