Wouldn't you expect companies that rely on a given project to have a vested interest in the project succeeding? I wouldn't choose to spend who-knows-how-many man hours on migrating to a new technology instead of paying a modest (for a business) fee for licensing something I rely on.
Your viewpoint is personal "I would do this" and for you it's easy, it's your money so you just write a check.
Companies don't work like that. Firstly because individuals get budgets, and there's no point wasting limited resources on free stuff. Secondly because individuals are accountable. There are procurement processes, multiple-level sign-offs, justifications, invoices etc.
In truth most OSS projects make it really hard to get "financial support". If you give away your product for free you make it almost impossible for a company to pay you.
My advice: if you plan to write OSS for a living -start- by understanding how company purchasing and invoicing work. Get that part right -before- you even decide what to build.
I set up a company, had a no-cost+open source version for download, and a money+open source version ("commercial") for purchase, both with an MIT license. The commercial version was faster, with more features, and included support, and it was in the marketing literature from the start.
The goal was to give users a way to justify the expenditure to their budget people.
It didn't help. I was even at an open source conference where one of the industry presenters complained about how hard it was to pay open source developers.
Thing is, the presenter earlier gave a talk about their extensive use of my software - first time I knew they used it.
I pointed out that I could get them an invoice within 10 minutes, for an improved version of the tool they were using, plus support.
They did not take me up on the offer.
I now generally interpret "it's so hard to pay for open source" as cover for "we've heard it's hard so it's our excuse for why we don't even try."
I've tried other approaches too, like a consortium model for new feature development and support/maintenance. It wasn't enough to be economically viable. Yet companies include that software in products they sell. A few years ago I asked one of them for money for support, and was told it wasn't in the budget. What they do now is ask the current maintainers for free support.
My advice: if you plan to write OSS for a living, work for a company where that project demonstrably saves them money and/or lowers their risk on external vendors. Do not try to be an independent open source software vendor.
I have yet to hear of a McDonald's sending a truck to the nearest soup kitchen and loading all food into it, to sell at the restaurant, because companies "take maximum advantage of any free resource". Well they don't do it, because it's seen as unacceptable. Why do we see it as acceptable in OSS?
Fundamentally the reason MD doesn't do that is because they don't have what MD want.
Companies are more than willing to exploit free resources whenever it suits them to do so. Dumping pollutants in air and water springs to mind. Leveraging public infrastructure and so on.
If my factory has a lot of trucks coming and going I don't "donate" extra money for road repair.
That all being said, I have no intention of writing OSS for a living. I contribute to FOSS for fun only, and I set my own schedule outside my day job.
Even assuming I can "just spend" that, I need an invoice. It needs to be captured by accounts. I can be quized on it.
Also I would rather pay one company $1000/month than 5 companies $100/month for the same service. To be crass about it, it isn't my money, but it is my time.
And it's pretty obvious why -- a purchase is a transaction with a clear expectation of what you're getting in return. If you donate, it's unclear what you're paying for and what the maintainer's obligations are.
The notion that you'd make some useful open-source project used by multi-billion-dollar companies and they'll throw a few pennies your way to make sure you keep the project alive is hippie bullshit.
Unless it's truly a well-established and well-governed project with a diligent maintainer at the helm (e.g. Vue.js), the only way companies financially support open-source is by contributing work or hiring the maintainer.
Yes, but that is abstracted away easily as "someone else's problem". Mature organizations with SCA and policy around it will often do a library review that catches using less mature projects.
This means that you get a bunch of small companies that can't/won't maintain or contribute back to the projects themselves, and few big companies using it who'd have the overhead to contribute back.
In some cases, for popular and newer stuff, that means that when a vulnerability is found, you have hundreds of companies and projects downstream from the bad code. Meanwhile, the larger and more mature orgs flag it and deprecate or mitigate it (through various, expensive means like WAF/RASPs)
And by then, it might even be completely unsupported, or worse, made breaking changes that strand many. Like a whalefall, it will feed hackers for a year.