Why aren't there blue sky research labs funded by curious billionaires? Xerox PARC's key computing inventions cost a total of US$48 million in today's dollars [1]. There may not be so much big cheap low-hanging fruit now, but there is still plenty within reach. Bezos could be doing this instead of or as well as Blue Origin (which he's been funding at US$1 billion/year [2]).
[1] https://www.forbes.com/sites/chunkamui/2012/08/01/the-lesson...
[2] https://en.wikipedia.org/wiki/Blue_Origin