You misunderstood my argument. My argument is that if forced to use Rust (given, say, a tectonic shift in the coding world where Rust becomes dominant - something many people are clamoring for), most average developers would have a difficult time writing secure code, because they'll have to keep a higher level of complexity in mind. Productivity is irrelevant. This is the classic trap of not being able to measure thing ABC, so you measure thing XYZ and assume that it's the same.
TL;DR: Let's see what happens when average C programers are forced to use Rust. Will their code be more secure? I see no convincing arguments one way or the other. Only measuring XYZs.