The whole article is a fantastic example of the Texas Sharpshooter fallacy. It finds a bunch of ideas that fit the authors thesis and ignores the thousands of companies working on hard problems that impact nearly everybody.
Even the examples in the article are sharpshooters. They drew a circle around a set of people and held them out as support for the idea that tech startups are solely focused one demographic. It's bad logic, but it's also wrong.
Single mothers? There's a whole litany of apps targeted at them. Like SupportPay (https://supportpay.com) for child support collections. Or CareLulu (http://carelulu.com) for finding child care options. The rest of the list (rural poor, out of work Americans over 50, and veterans) can all very much benefit from the huge number of startups trying to make educational accessible over the Internet.
Energy startups are out there trying to help folks shave dollars off their energy bills (shamless plug: I work for Gridium at https://gridium.com - check us out!). Healthcare startups are out there trying to solve hard problems with medical record keeping and information access.
Hell those inwardly focused tech companies like Stripe and Gusto have made starting a small business the easiest it's ever been. Want to solve problems for veterans and the out of work over 50 crowd? Remove the friction around starting a small business and let them put a lifetime of experience and knowledge to work.
So ya some people are out there trying to solve the small problems. That's great, because sometimes solving a small problem leads to a big one. Amazon went from selling books to completely redefining how commerce happens for a large number of people. Solving those small problems also creates a class of person with experience in company building. Maybe they'll put that towards solving those generational problems in a couple of years.