> No, the license is how they legally give away permission to use material that is legally subjejct to their exclusive rights by virtue of creation. The license may be a contract license that, as you suggest, involves mutual exchange of value, but for many (especially permissive) open source licenses it is a gratuitous bounded grant of permission which has limits but does not involve giving something of value back to the creator.

Wrong. What they want in return is either credit or derivatives of the software. It's disingenuous to suggest that all these authors specifying, in a legal document, the exact mechanism by which to pay them back don't know what they are asking.

If you're not happy with that trade, then don't make it.