Like are we empirically seeing less Rust CVEs? Adjusted for popularity of software and perhaps age of software.
The question is whether your software will be in use long enough to be worth the cost of change more than whether it's a good idea in the long run. For Linux, I'd argue that that's likely. At least new code would ideally be contributed in a safe language, where practically possible (there'll surely be places where you need to deal with memory as a kernel)
Relevant article: reducing memory vulnerabilities through a combination of memory-safe languages and an exponential decrease of bugs as existing code ages https://security.googleblog.com/2024/09/eliminating-memory-s..., from which I'll also quote my reference for [1]: "A large-scale study of vulnerability lifetimes published in 2022 in Usenix Security [...] found that the vast majority of vulnerabilities reside in new or recently modified code"