I can't speak for Jack, but I can speak to learning both programming skills and business skills. When you self teach programming, you usually don't end up shipping a product that you're not sure will work. Most of the time, you can try things and the compiler and some basic QA will tell you if it worked. Unless you don't test your implementation at all, you know how well you did when you push your code.

In business decisions, there is no test bed. Your choices play almost exclusively in time, money, and human capital. You can definitely try to self learn in that environment, and many successfully do, but it's a lot easier to screw up to the point where you can't continue.