Since Sustain OSS, we have been working on new ways to help maintainers sustain their maintenance efforts and we are developping a Maintainers’ contract, based mostly on monetizing the commercial usage of the trademark goodwill of OSS projects, not the code copyright. Then the code stays open source as OSI and FSF definition, but maintainers can get fees from companies using project trademark assets for commercial purposes.
In others words “the code of the project is free, the swag of the project is not.”
After all, the work, the governance, the trust of an open source project has value that is not represented by the code but by the name/trademark of the project, so maintainers can get a part from it, from companies using it for commercial purposes.
This is just the democratization of the Redhat model, with RHEL and CentOS. RHEL is the trademark enforced version of the software where CentOs is the trademark free version. Like that, Redhat can control the commercial ecosystem of the open source software also capture the value of support on RHEL because of the trademark enforced software commercial obligations.
Trademark is not enough used by maintainers to get funding to sustain their projects maintenance, although it keeps the code free/libre! (as free beer and as freedom).
Here is the draft Maintainers’c contract that has been getting feedbacks now from a dozen of OSS lawyers,