This is the sad truth about open source software - if you have a good product, giving others access to the core software often means you can develop a community that will help you develop and create a company around it. But a large company will often be able to produce a more commercially version - cheaper, better support, wider availability, integration with other services etc.
Paying for developers to work on some open source project that you rely on, absolutely, great idea. But trying to monetize an open source project itself is myopic - obviously the solution if you want to do that is to make the project not open source as you say.
This isn't a problem with open source software, it's a feature and it's part of why it's so ubiquitous - no one company pulling the reigns who can fuck it up.
But the point is people are trying to make a living using their software development skills, not specifically make money from open source. As part of that the question is should they release their code as open source or keep it closed.
Then they shouldn’t get shocked when it works against them. If you are releasing open source (especially under permissive licenses) you are relinquishing your rights - so do it from a view that its charity to the world, but don’t expect to get all the compliments for doing OSS work but also _expect_ market rates for the work you did. No one agreed to pay you for it, no one agreed to pay you royalties for using your product in theirs and so forth.
ps I was having a go at non GPL licenses, because they simply give away everything.
What is PD?
Public Domain software [1].
Where does the money come from to pay those developers to work on open source?
Developer/Designer/QA/PM/Whatever time is the thing that actually has meaningful cost here, not the act of sending bits across a wire. So that's the thing that the market should be paying for.
The difference with proprietary software is just that you can get people to pay for those man hours after release time - in OSS you don't have that luxury, and pretending that you do, or that you're actually fundamentally charging for something else is a mistake.
If you open source, anyone can use your code. In the previous world this was good. In the new monopoly world, the giants clone your product, make it a paid feature, and outcompete you. You'll be out of business with nothing to show for it.
Famgopolies shouldn't be allowed to access open source unless they open source their entire stack.
Then, once you cloned the software, you still need to convince the customer base to switch.
It's far easier to simply write a check and get code, talent and customers at once without delay.
I like that you're single handedly trying to make this word happen against the crushing weight of social inertia and multibillion PR departments. It feels very appropriate for the topic.