You need to re-read Elon,

It's not that he will solve FSD, Tesla is valuable until FSD is solved as then it becomes just a car company.

And he picked the correct impossible puzzle that will never be solved. Same with the SpaceX premise.

The market value is the desire of groups of people that it be solved.

The lesson here is what impossible problem is our domains that we can market that our company is attempting to solve it and which of those impossible problems happens to intersect with a large group of people wanting said problem solved.