What? I create something, and I shouldn't be able to sell it? What?

Software isn't a "thing" so there is nothing to sell. The only way to monetize software is to monetize the labor of writing it directly. When you "sell" "licenses" to software, you're just double, triple, N dipping on monetizing labor that already happened.

The alternative is charging to write software, which is actually how most people (employees) make money writing software. Corporations take advantage of the difference between paying people to write software, and charging people over and over again to use the same software that has already been written.