Maybe Rust moves slowly, but not nearly as slow as Go. I know because I use both languages daily. I spend almost no time in Go code keeping up with deprecations, new APIs and new language features. Not all of those things need to go through the RFC process. For example, I don't think there's any backpressure against deprecating stuff right now. As soon as a replacement comes along, a deprecation pretty routinely occurs just a couple releases (a few months) after it. I don't spend a ton of time in Rust responding to churn, but it's definitely noticeable.
This is why I've been bleating a bit more now than I have before about reducing churn.
N.B. On reflection, perhaps I do have some bias here. My daily work on Go is mostly for $work, and involves one large codebase. My daily work on Rust, however, involves maintenance of dozens of crates. So if there's churn, I feel it repeatedly. So its effect might be magnified for me personally.
This is why I've been bleating a bit more now than I have before about reducing churn.
N.B. On reflection, perhaps I do have some bias here. My daily work on Go is mostly for $work, and involves one large codebase. My daily work on Rust, however, involves maintenance of dozens of crates. So if there's churn, I feel it repeatedly. So its effect might be magnified for me personally.