Bill Gates builds Microsoft, Steve Jobs builds Apple, Mark Zuckerberg creates Facebook, as well as other drop out entrepreneurs. By creating something they also increase the assets they have built since the beginning.

All their assets have a snowball effect, like a snowball that keeps on rolling and getting bigger, most people make the mistake of swapping the time they have with the money (employees), which means they are stuck forever in the thought of spending time to earn money, but if you invest your time for skill / ability / passion and create something from there then what you create can make money even while you sleep.

As an example of whether anyone would pay Mark Zuckerberg / Bill Gates billions of dollars as an employee or freelance programmer ..?

They start as early as possible, build assets when they are young and create something from the assets they have built. They know that getting started is the only way they know what it feels like, they do not need permission from others to create something, and by creating their own snowball, all the assets they have will grow larger as time passes.