Absolutely, I don't think any sane Rust zealot would argue that Rust can compete with Go/Dart productivity. The argument can be made that Rust code has a lower maintenance cost over time, though, and that productivity may not drop as much as the system becomes more complex.

Even with this relative improvement, though, I question if it's enough to overcome the shorter compile and test loop the other languages have, or the mental overhead of managing lifetimes and ownership.