The thing is, time is money. Leisure time is one privilege of the rich, or lucky, which leads to unfair compounding advantages (like philosophy as well). "Normal" people (as in, if you selected them at random) don't have the time to learn the special skills required and also invest the time to develop the very specific type of product you are talking about. So, in order to start a business, you need to have a break. It can be getting lucky with your job, a windfall, or just gambling some precious savings or time onto your idea. And then, most of the time, it fails, and most people cannot afford to retry. Those that manage anyway are the exception, not the rule
For example, infoproducts (or any kind of digital product) are very cheap to start up. They take time, but not necessarily a lot of money.