[zozbot123]

Open source software existed before closed-source software was even a thing. Software used to come in source-code and freely-redistributable form; it was basically funded as a loss leader for things like hardware and support, that could be billed for. Many companies today which fund FLOSS have very similar models, only with other sorts of value-added services being added to the toolset. Others have even managed to pay for FLOSS directly via crowd-funding.

[weberc2]

To be clear, "OSS predates CSS" is not a refutation for "CSS makes the OSS ecosystem larger and more robust". Apologies if that's not the point you were trying to make.