[eaurouge]

No, the reason many entrepreneurs are building social networks is because many of those entrepreneurs don't have the technical chops to cure cancer or to solve more difficult problems. Solving difficult problems often requires either deep domain knowledge or solid technical expertise in areas more challenging than web/phone app development. There's a much higher barrier to entry.

Mind you there's a fair number of entrepreneurs out there solving difficult problems. But they're not as many and they don't get as much press.

[paul]

People choose what to focus on based in part on the expected benefits.

I was very interested in biology in high school. Part of the reason that I ended up working with computers instead is that the feedback is much faster (compile and run) and the leverage much greater (e.g. Bill Gates got rich with a software company, not a life sciences company). Needless to say, I don't regret choosing software over biology.

[eaurouge]

I agree that software solutions can be leveraged for more financial success than (say) hardware solutions. I also decided to switch focus (at least temporarily) from what would have been a medical devices startup to software for that reason, among others.

But I think an entrepreneur's skill set is more of a limiting factor in the type of startup he/she can decide to pursue. After all there are problems that are potentially more lucrative than social networks but if you don't have the domain expertise or technical knowledge to solve those problems you may not even know they exist and if you did, would not be able to solve them.

There's a more extensive discussion on this here: http://swombat.com/2012/1/19/idea-reach-cofounder-myth