I think you have a point that yes, programming languages depend on the domain a program is in. If the program only handles up to 10k customers, it can be programmed in javascript and can indeed keep its entire database in RAM. sqlite even has a mode for this. A LOT of custom software is in this "small" domain. However, when you get to millions or billions, maybe you have to optimize and create a backend. What should this backend be written in? Previously the answer might have been C++. But now it's Rust.

Personally, being a Rust enthusiast, I think that Rust's benefits don't just unleash when you think about performance, but also when you think about large codebases. Such codebases are usually the scene for refactorings. In a dynamic language like js, these are extremely hard to pull off. In Rust, the compiler won't stop yelling at you until you have cleanly finished the refactor. I love refactoring Rust codebases, even ones I didn't write, while in C++ or other languages it's extremely annoying.

And note that while C++ enthusiasts might have believed that everything should be C++, not everyone followed them. Many people still stayed with C. Many still do even with Rust around. But there is a small group of people for whom Rust is such a great improvement that they take the portability cost and switch to Rust. Linus is heavily anti C++ for example, but he's open to adding Rust to the kernel.