You're making a couple assumptions I disagree with. Even when I was under 40 I knew of more problems that needed to be solved than I could possibly address. E

You're making a couple assumptions I disagree with. Even when I was under 40 I knew of more problems that needed to be solved than I could possibly address. Every job I've had has exposed me to industry problems that were big... and you can found a company in an industry, be a single founder and then hire people who have domain expertise. Domain expertise doesn't mean one has to be a cofounder. Also, consider does this domain expert have the background in startups that would be useful? Or were they being an employee in that domain? I can think of a half dozen purely technical problems that would improve a billion people's lives-- and I'm talking purely software here.