The problem is the people who use the library don’t have access to the money. They’re just some dev trying to build something and your library is one of their 500 dependencies. The idea of needing to pay for a license means they have to stop building and get other people involved who may or may not approve, which may not be an option if they have a deadline. They will probably just try to find some work around to avoid this.

I wonder if a better approach is to move hundreds of libraries into some kind of joint bundle (a humble bundle). Let companies buy access to them all with one procurement, and also you’ll have more negotiating power and pull if you have a bigger group.