Countless time I have seen other people complain as well. There are articles about it even. Can't find the YouTube link now but recently a gamedev abandoned Rust due to compilation speed alone because iteration speed was paramount to their creative process.
Handwaving isn't going to make it any better. And thinking Go/TS compilation speed are comparable to Rust is, a handwave and a half to say the least.
Cargo check and friends are subpar for AI because they actually need to run the thing and unit tests for efficient agentic loops.
A single loop might recompile and rerun the application/unit tests enough times that slow compilers like Rust and Scala become detrimental.
I'm not saying that Rust compilation time is comparable to Go/TS, I'm saying the blanket claim that Rust iteration speed will be a bottleneck requires context.
I definitely agree with you that it is a complaint that is often repeated online, but that doesn't make it universally true. In my experience it's a claim that is often echoed without proper context.
Particularly in the case of AI Rust recompliation times in my experience have not been the dominant cost, but are instead overshadowed by inference time, the agent working through different approaches, etc.