There are places a language could be a better fit, but which haven't adopted it. E.g. most languages over typescript on the backend, most systems programming languages over Java for games.
If you define success for Rust as "everything is written in Rust", then Rust will never be successful. The project also doesn't pursue success in those terms, so it is like complaining about how bad a salmon is at climbing trees.
That is however how the Rust Evangelism Strike Force does it all the time, hence these kind of remarks I tend to do.
C++ is good for some things regardless of its warts due to ecosystem, and Rust is better in some other ones, like being much safer by default.
Both will have to coexist in decades to come, but we have this culture that doesn't accept matches that end in a draw, it is all about being in the right tribe.
So... Like, what? Do you agree that there is no technical reason for LLVM to be written in C++ over Rust?
Have you considered that you perhaps do more damage to the conversation by having it with this hypothetical strike force instead of the people that are actually involved in the conversation? Whose feelings are you trying to protect? What hypocrisy are you trying to expose? Is the strike force with us in the room right now?
I assert there is no reason to rewrite LLVM in Rust.
And I also assert that the speech that Rust is going to take over the C++, misses on that as long as Rust depends on LLVM for its existence.
Or ignoring that for the time being NVidia, Intel, AMD, XBox, PlayStation, Nintendo, CERN, Argonne National Laboratory and similar, hardly bother with Rust based software for what they do day to day.
They have employees on WG14, WG21, contribute to GCC/clang upstream, and so far have shown no interest in having Rust around on their SDKs or research papers.