> Outside of software and data science, is there any industry where the software landscape is dominated by the OSS players?
Academic publishing, maybe. Many of them rely on LaTeX, especially the mathematics journals, but even this is changing if I understand correctly—more journals are accepting submissions in Microsoft Word format.
True, but LaTeX only exists because of computer science researchers (largely Leslie Lamport from what I understand.) They had a need, and built a tool to meet that need, and the rest of the industry benefited.
There's less overlap in needs between software and mechanical engineering, for example.