I’m personally rather bored with the hobbies and tastes of these modern tech billionaires like Jeff and Elon. A few years back, there was a total global circumnavigation of the world in a solar powered 2 person airplane based in Switzerland, I forget the project name. This thing did not have to land to charge batteries but could stay aloft indefinitely, albeit at a very floppy wing surface area to weight ratio, and the resulting vulnerability to wind and low speed. Such a project or something that presents and actual investment that only a billionaire could provide are eschewed in favor of juvenile pissing contests like Mr. Branson and Mr. Bezos pursue