I won't deny the comfort value of yachts and private jets, but I doubt that this material comfort is the main value proposition of these things. Instead, it's status symbols, status above slightly less rich people. The yachts are in a way an epiphenomenon of intra-elite social competition, and if you don't manage your network well, you can easily lose out in the next generation. Investment into social relations is what really matters. And when you're generationally rich, you typically think about making impressive impacts over society, the kind that impresses your social circle, based 9n their philosophy, which typically happens to be self serving but with just enough other stuff to not seem to crass. Taste is the highest status thing,not intelligence, not skill.

It's hard to extrapolate. What will be the goals and motivations of this super elite? Let's say all of us normal people just die off either starving or just by not reproducing any more, just watching VR, sedated with subsidized happiness drugs. Let's just suppose that. What then? Will the rich keep reproducing? What will limit their reproduction if material abundance is there? Will the elite families keep each other in check not to over-reproduce? Or will these people repopulate the earth, each living on yachts and in comfort, living an elite life? Surely that will bump up against all kinds of limits, similar to what the current earth-populating humans are facing. You can't have a super yacht per person to an unlimited amount of millions of people. At some point they will have to willingly not reproduce despite having all access to robot care, robots watching your every whim etc. I don't see any stable endpoint.