My point was that José and Chris being continuously employed working on the language and Phoenix respectively (by the companies I named) are probably considered a form of commercial backing by most people. If you want to split hairs about specific timing or magnitude of investment, that's kind of nitpicking IMO. It's not grassroots at basically any point.
José founded Dashbit after Plataformatec got acquired but up until ~2020 Plat directly funded the creation and iteration of the language, with it originating as an internal research project.
Mozilla alone invested an eight digit amount in Rust.