Instead of expecting corporate users to pay (which can be difficult, corporate finance depts are good at spending large sums of money, but suck at small expenses), or acknowledge use (company policies might mean employees are not allowed to), perhaps the major hosting providers such as Github and Gitlab can directly remunerate open source repo maintainers depending on the popularity of the hosted repo? Surely they make a lot of money by more and more devs adopting their service?
Edit: I am the owner of an open source repo on Github which was quite popular a while ago, but fell into disrepair because I could no longer find the time to maintain it. So I understand the pain of this person.
I like the idea, but I don't think it should be on github's shoulders to directly fund opensource. They do more than enough.
What I'd like to see is a fund which companies who use opensource are expected to contribute to. For every 100 employees at your company building on top of opensource software, I'd like to see at least 1 employee's salary funneled into the opensource ecosystem. That fund could have a default division based on community needs, or each company could specify how their donations are allocated. And if they donate by having their employees publish generally useful packages, thats fine too.
I don't think it should be compulsory, but I want this stuff to be very visible. If someone files an issue against one of my projects, I want to know if the organization they're part of contributes to the community, and how, and to what projects. If you want me to donate my time to fix an issue you're running into, but you don't contribute back in any way, I'd like to know that before I decide if I'm going to spend my weekend helping out.
Right now there's no incentive for companies to contribute to opensource because contributions are generally invisible. And bugs they run into usually get fixed anyway. If we tie a company's contributions to their reputation, and make reputation affect public standing, we might have a shot at changing social norms.
Edit: I am the owner of an open source repo on Github which was quite popular a while ago, but fell into disrepair because I could no longer find the time to maintain it. So I understand the pain of this person.