Actors do not win Oscars doing great performances in bad movies.
Scientists do not win Nobel prizes working alone or in bad work conditions.
I always take these appreciations at face value.
That said, not trying to undercut anyone's appreciative statements, especially the one from OP in his repo towards Rust! Obviously people (and programming languages, for that matter) aren't simple drop-in replacements for each other in real life. You have to be inspired and empowered by them.
That personal motivation or rapport component is probably what was being missed in the post to which I replied.
But you never know, maybe in another language he would have done a much better project, maybe not. Actually, in alternative universes everything would probably be different. If Python didn't exist this project would maybe not exist too, and would be at least a little different in any case, so he could have opened the full version to Python codebases too, and that applies to all other languages.
He might also not have chased the project if he weren't working in an ecosystem he particularly liked, so who knows, maybe it wouldn't have happened without Rust.