Agreed, especially as the proprietary alternatives are starting to incorporate more and more Rust, even Windows is starting to rewrite their core libraries in Rust.
On top of security though, its going to be important for continuing to bring new maintainers onboard. Less and less people are learning C, especially to a level proficient enough to be a kernel maintainer. As Rust matures even more, C is effectively a legacy language at this point, a C++ won't be too far behind either, and Linux is going to be hard pressed to find maintainers as the graybeards retire.
I'd argue that would make even less of an incentive for manufacturers to make Linux drivers.
We are already kind of seeing that in the gaming space. Why bother making a native Linux port if it works fine enough on Proton/Wine. We effectively end up with Win32/Linux