For me, here's the list of industries I'd love to try and disrupt, in no particular order: clean energy or clean water, health care IT, public transportation, 3rd-world agriculture, cybersecurity, the US education system.
Or, here's some cool tech areas that I'd love to play in, maybe disrupt something, but at least it would be hugely fun: AI, flying drones, quantum computing/communications, genomics, space travel. Also, see the Yudkowsky Scale [1].
You see where I'm going with this. With all his money and all his talent, Sean Parker has decided to solve the problem of "my random video chats had too many penises in them."
Not everyone can be Elon Musk, but once you've got 2 billion dollars, damn man at least give it a try.
To be clear: I have no problem with software startups that start by solving small problems or by bringing a tiny bit of joy to people's lives. But there's also plenty of people already doing that. I just think the calculus of how you spend your time has to change when you have more capital at your disposal than 99.999% of the entrepreneurs on the planet.