While I respect the author's anecdote, this doesn't match my experience. I've been programming for 20+ years across a wide array of languages and I'm by far the most productive in Rust.

With a competent teacher, experienced devs should be able to pick up on the memory model pretty quickly, and that is really the only initial blocker to productivity. After that a dev can essentially write procedural code if they want, like other common languages, while refining their thinking and practices towards idiomatic Rust.