Yes, I think I agree that a co-op [1] seems like an interesting solution to this problem. I think the work around social benefit corporations (which are still for-profit) is somewhat related. I think the model definitely matters as a form of signaling intention. If the organizational form is too exotic or non-standard, it may drive people away (even if it is a better way of doing so).

My viewpoint is heavily Western-world skewed, unlike other countries where co-ops are more commonplace. Apologies in advance, I'm always trying to escape such a singular world view.

Your model might actually make businesses very happy, actually. Dealing with tons of different open source licenses no doubt adds legal burden/costs to commercial efforts. It would simplify both payment and legal terms. The tricky part then becomes getting enough people to contribute their work - it would be as much a marketing pitch to contributors. Probably similar in difficulty to trying to start a marketplace where you need both contributors and consumers.

I suppose one thing you could do was have a "pay-what-you-can-or-nothing" tier as an option that your contributors could choose. This way, there is still a both open and "free" version in the cases where people choose to offer that for their intellectual property.

I'm thinking a little bit of a variation on Patreon in the back of my head as well.

[1] https://en.wikipedia.org/wiki/Cooperative