Maybe I misunderstand your comment as if we've run out of ambitious things besides those that border on science fiction. In that case, I think the market is those of us who think there are more tangible ambitious things right in front of our faces. And in front of those with the resources to make a difference ie, fighting starvation, authoritarianism, inequality, disease, genocide. Are these too boring?
The longevity people are very much into preventing disease, and they're going after the most significant root cause rather than playing whack-a-mole with individual conditions. Which somehow results in them being vilified.
> fighting authoritarianism, inequality, genocide. Are these too boring?
Right, have the tech guys spent their money on politics - that seems to be working out well.
> fighting starvation
We have enough food in the world: we don't choose to share it or distribute it. Politics.
> fighting disease
Politicised within the US (measles, birdflu, NHI, health insurance), and similarly politicised within my own country (US social media is only partly to blame).
Bill Gates put a lot of money towards helping fight Malaria and other health issues: I would guess no other rich dudes wish to get similarly tarred.
We should devise a system that gathers all human resources and applies them to a set of goals, like you mentioned. The smartest people in the world should get together, determine the most pressing issues and command all of humanities resources into those problems. We can remove a lot of waste like frivolous consumerism, endless choice and competition. Why has no one ever tried this before?
No, they're not boring, but they're qualitatively different types of problems.
Going to Mars and living forever are primarily technical problems.
Starvation, authoritarianism, inequality, and genocide are primarily political problems.
The resources and skills used to solved the former set aren't broadly applicable to the latter set, though it is easy to find examples of people who are good at solving one of these sets of problems who assume that they'll be good at solving the other set as well.