That's specious reasoning at best, and for multiple reasons. The bulk of software development platforms standardized and uniformly built their services on FLOSS

That's specious reasoning at best, and for multiple reasons. The bulk of software development platforms standardized and uniformly built their services on FLOSS, and version control ends up being a tiny version of the whole offering. In fact, the bulk of their business model is based on providing version control services as a loss leader, as none charge for it. They charge for ticketing, CICD, package hosting, Docker image registries, etc. Also, some of them offerer Mercurial as well. Somehow Mercurial still failed to gain traction.