Rust is very popular and quickly getting adopted. The number of Debian packages that use Rust libraries more then doubled and is now at 8%
An observation I've made about Rust is that because it eschews OOP, it tends not to "scale" to large development teams for single applications. It's great for CLI tools, small web apps, etc... but after some scale it runs out of steam.
This is exacerbated by its glacial compile times compared to other languages, even C++, let alone C#.
I just can't imagine something the size of SharePoint being developed entirely in Rust!
Linux is written in C and "scales" to large teams. If folks were willing, I think most of Linux could be written in Rust.
Chromium is similar. It's practically an operating system now, it even has USB drivers! I had to compile Chromium from scratch once, for which I spun up a 120-core cloud VM with 456 GB of memory so that it wouldn't take all day.
With Rust... that would take all week even on that box.