alt Hacker NewsBut "learning a new language" can mean multiple different things. It can mean learning a language at a superficial level, but it can also mean learning the depths of the language, or the depths of the ecosystem, or both. For instance, for Java, how many professional Java developers understand and know about memory consistency and the Java concurrency model? Or some other niche topics that might be important in some contexts? How much time would it take for someone to learn the ins and outs of unsafe Rust or pinning in Rust, or other involved topics? Or Rust's gotchas?
There are different depth levels of learning a language. And there are lots and lots of topics besides the specifics of various programming languages or their ecosystems.
I barely knew Rust, yet I was able to rather easily dive into and fix significant bugs in a Rust project that the experienced Rust developers on it had struggled with, possibly struggled for months. But the cross-discipline set that was relevant for solving those specific bugs was also a good fit for my competencies as well, and I have lots of experience with OOP, FP, systems programming, etc. FP is not necessarily learned in a day.
So what it sounds like is that you're assuming that the current C-developers are the top 1% of C developers and therefore need to be in the top 1% of Rust developers, familiar with all niches.
I don't think that's a reasonable assumption either which way. So it sounds like you're arguing against people learning a new language and using it in a professional or open source context because learning takes time and they're not instantly experts.
But.. never getting started is a surefire way to lose the race. Everyone needs to start somewhere. Plus, look at it from the inverse perspective. The newer generation(s) of programmers today are more likely to learn Rust to a deep level than C. And those up-and-coming developers are the maintainers of the codebase in the future.
Again, this all ties into thinking long-term vs short-term.