In my personal experience, the rate at which Claude Code produces suboptimal Rust is way higher than 1%.

That is dependent upon the quality of the AI. The argument is not about the quality of the components but the method used.

It's trivial to say using an inadequate tool will have an inadequate result.

It's only an interesting claim to make if you are saying that there is no obtainable quality of the tool that can produce an adequate result (In this argument, the adequate result in question is a developer with an understanding of what they produce)