[bick_nyers]

I wonder if "pay to compile" would work well. In other words, open source your code to the world, but if you want to download an .exe you need to pay an upfront cost.

Obviously doesn't work with all types of software, but even something like a C++ backend library (like OpenCV) you could open source the C++, but sell access to the python bindings.

[elcritch]

I've pondered in the past about paid "documentation". You have basic opencv docs but charge for the in depth docs. Really it's sorta a thing when people buy books from SMEs on an open source project.

[imtringued]

The problem is licensing fees. The fee itself may be insignificant but you need to track who has to pay who and this requires license keys and licensing servers and all the logistics to get these things to the right places.