I've heard this is not the case in all industries, and that many industrial projects (as in factory automation) use Windows, however crazy it may sound. But I don't have a first-hand knowledge of this.

All software I've worked with was built from scratch. We've used plenty of libraries, but this was all generic stuff, all the "comprehensive ecosystem and foundation" was our own. But compared to the actual business logic, that foundation is pretty simple - you need math libraries, some sort of RPC, logging, process management, replay/sim. This does not include device drivers - there is a very good chance you'll need to write them scratch anyway. And none of this is even close in complexity to things like path optimizer.