His point is more that they're really Web Developers, not businesspeople. That their expertise is from direct experiential practice with an extremely narrow type of software business.
He's a business school type, so this rankles. His whole world view is based on broadly applicable business practices, grounded in theory and hypothesis, backed up with data.
His kind of "business person" doesn't even necessarily start one business, even if they might see opportunities everywhere — they get brought in as management. But if they start one, they're probably going to start more.