Even at +4c there will still be plenty of “nice” places for billionaires to fuck off to and build a nice little rich people commune. Hell, a +6c world is still the garden of eden in comparison to Mars.
Yes there’s a lot of interest in Mars right now, but it’s really is just mega rich nerds. Hell, if I was mega rich, I’d make an aerospace company too, space is cool.
The rich peppers are buying up land and building compounds in climate safe havens, like New Zealand.