Not mainstream language 'fine', but fine.
Type "Rust" into a job search engine and see what comes up, it's mostly blockchainy stuff. Or a few shops that are "looking into" doing Rust for new projects (which is encouraging, but hard to say how that will shake out).
I personally won't touch anything "crypto", so I feel somewhat lucky to be getting paid to work in Rust right now for something that isn't. But I fully expect that once this gig finishes, it'll probably be back to C++ for me.
Those are just the loudest people. Web3 companies depend on hype so they shout all over the web about anything they can, including how they're using the hot new language for blah blah blah and you can come and write it with us! (As long as you're willing to be paid in worthless tokens.)
In normal companies there is plenty of Rust use but you don't hear about it as much because it tends to be initiated internally by people who weren't hired as Rust programmers, and it's used for new projects that take a long time to get to the point of needing new employees. I know in my company it was at least 2 years between when we started using Rust and when we wrote "Rust" on a job advert.
by dictionary definition, rust is not mainstream. it's not normal (common, typical, customary) for an engineer to interact with rust
It's only 3 times less popular than C. As I said, very weird definition of mainstream.
How is that not mainstream by even your own definition? It’s consistently a part of the current zeitgeist.