But those aren't the only kinds of companies worth building, and "young entrepreneurs from top schools" aren't the only people who can build good companies. We shouldn't look to them (err, ourselves) as "humanity's only saviors". Which I think this article makes the mistake of doing.
A similar problem that I have with this piece is an over-reliance on entrepreneurs - that is, the free market - to solve the problems of "the unexotic underclass". The free market will solve the problems of people (and businesses) who have discretionary income. That's how capitalism works. Capitalism also has a lot of inequality baked-in. He shouldn't be surprised that difficult-to-serve, low-income individuals are failed in America.
Keep in mind, too, that the other part of "discretionary income" is "discretionary". Schools, Hospitals, Government Agencies like the VA? They typically have terrible purchase processes (and generally poor management) that make it almost impossible for entrepreneurs to sell to them. I recently folded an Education Technology company because schools are so difficult to sell to and have so little money. Don't blame the entrepreneurs here; blame a government which over-regulates and under-funds schools, the VA, and other services. (And then vote to make a better one!!)
All that being said, I do agree that there are opportunities for entrepreneurs in these markets. They may be hard to find, but we're not going to do it by holing up in Tech/Wealth bubbles like SF and NYC. Spending some time in the heartland may be a great way to find those rare business models that could profitably serve the underserved.