Why are Yachts so common among the super rich, but neither airships, nor gigantic flying boats are even a thing nowadays?

I was watching some videos on youtube about superyachts a few months ago and the superyacht lifestyle just sounds pretty dull. They all look alike and only differ in size really. Helipads are nothing out of the ordinary but that's it really.
I would at least want it to be a seaplane tender for like a rotax powered SeaRey and then I thought it would be even cooler to have a giant flying boat. Think Sprouse Goose but with modern materials, it would be insanely expensive, but from what I can tell, that's kind of the point.

And as for airships, I'm not the biggest fan but I figured there'd have to be at least some rich assholes who want an airship that dwarves basically any man made vehicle. Again with the technology and materials of today, why doesn't this stuff exist apart from like warbirds?