The problem seems to be that there's not much demand for people to solve those problems (not that I agree that all of those are worthy goals, particularly the "get rid of lawyers" bit).
Solving some of the things you mention could produce immense benefits for everybody, but it seems like the common wisdom is that it's too risky to pay people salaries equivalent to "finance/entertainment/social media smart people salaries" to work on them, at least not in the same quantity as those industries hire.
Finance, entertainment, and social media companies are out there digging through resume sites and college campuses, actively looking for smart people to solve problems, because they are really sure they can make enough money to compensate them well for their efforts, and have a lot left over.
I'd love to work on energy generation, space exploration, brain computer interfaces, or longevity, but I expect I'll be working on more mundane problems until my student loans are paid off and my emergency and retirement accounts are back to where they should be, because there's reliable money in mundane problem solving.
Of course, I may not be smart enough to help out on "big problems," or I may not have the right connections, or enough risk tolerance. I still hope to find out one of these days. :)