This is where the supply chain metaphor — and it is just that, a metaphor — breaks down. If a microchip vendor enters an agreement and fails to uphold it, the vendor’s customers have recourse. If an open source maintainer leaves a project unmaintained for whatever reason, that’s not the maintainer’s fault, and the companies that relied on their work are the ones who get to solve their problems in the future. Using the term “supply chain” here dehumanizes the labor involved in developing and maintaining software as a hobby.
If supply chain in crass then labor chain, but a supply chain is always a labor chain. Microchips and silicon don’t produce themselves. I fail to see how a chain of dependencies is uniquely dehumanizing.
I think, the point is that people work on this stuff as a hobby. You can only expect people to provide you with labor, if you pay them. And “supply chain” does imply to me that updates keep coming, which fosters that expectation.