I think the "social factors" section is the most significant. I've heard plenty of anecdotes of people stating that they "code defensively" in C, because it's too easy to mess things up. Whereas with a language such as Rust, you're able to be more aggressive in your optimizations without feeling like you're walking through a minefield unassisted. The end result is that the language with more constraints lets you be more safely free in your implementation.