You're not wrong but I think it's sort of irrelevant. Rust is cool but from my understanding, graphics card drivers are almost an entire OS in itself. I don't think Nvidia is writing a new driver for each GPU, I think they're using a core driver codebase and making relevant modifications for each card.

My point is that I suspect that the Nvidia driver is a decades-long project, and dropping everything and rewriting in Rust isn't really realistic .

Dropping everything is not necessary when porting to Rust, it can be done incrementally and starting with high-risk interfaces.

Which is what Microsoft and Google have been doing.