I made a very good living developing open source software for more than a decade. Nothing about open source software precludes one from making money, it's just a different business model from closed source.

A business model that supports a tiny fraction of the market. To the extent there is money in FOSS, even then most of it is provided by the funding of big tech (a whole host of some of the most widely-used FOSS, like Linux, LLVM, Go, Rust, C#, Typescript, VSCode, React, are all obviously corporate-backed). Independent developers who can make a living selling FOSS exist, but are absolutely on the fringe.