It's not as widespread in these companies as you and many Rust evangelists imply it is.
Specially because it's not a drop-in replacement for C++. As Zig is for C.
So when Zig hits 1.0 these companies will probably consider Zig much more than they do today. Understandably.
First of all, if I am an evangelist of anything, it is about safe systems programming with automatic resource management languages, if I had a magic wand, we would be talking about languages like D and AOT C#, not Rust.
Secondly, let us know when Amazon rewrites Firecracker in Zig, Android replaces Rust with Zig, or Mark Russinovich goes to some Zig conference explaining why Azure is dropping Rust for Zig,
"Mark Russinovich, Microsoft Azure CTO tells Rust Nation UK 2025 why Azure is moving to Rust from C++"
https://www.youtube.com/watch?v=SmUprpjCWjM