[IsaacL]

A few ideas below. You mention startups trying "to make as much money as possible as quickly as possible" - I personally quite strongly believe that companies that focus on long-term profitability also happen to do a lot of good for mankind.

- cure for cancer

- cure for malaria

- cure for aging

- cheap fossil fuel extraction from low-quality deposits

- safer nuclear fission

- nuclear fusion

- lower-cost space travel

- space elevator

- space colonisation

- intelligence augmentation

- safe artificial intelligence

- desktop nanofactories

- nano-machines

[XorNot]

Of these, fission/fusion/fossil fuels are the only ones start ups might touch. And even there, it depends on a lot of physics turning out favorably.

[saboot]

At least the Helion guys believe they have a good shot at it http://www.helionenergy.com/