What he was working on is a financial service, not just a consumer web app. He changed the world by making payment and ecommerce easier. It may not be sci-fi or anything like, but what he was doing was of importance.
Right, but he didn't jump right into future-tech industries; he had a huge pool of personal capital to draw on, and only himself to answer to in using it. The point the parent is trying to make is that there are probably a lot of people working in less glamorous businesses who would love to jump to working on the cutting-edge, but they don't have access to hundreds of millions in personal funds.
