> might as well have used C, the dollar cost is the same.

When your unsafe area is small, you put a LOT of thought/testing into those small blocks. You write SAFETY comments explaining WHY it is safe (as you start with the assumption there will be dragons there). You get lots of eyeballs on them, you use automated tools like miri to test them. So no, not even in the same stratosphere as "might as well have used C". Your probability of success vastly higher. A good Rust programmer uses unsafe judiciously, where as a C programmer barely blinks as they need ensure every single snippet of their code is safe, which in a large program, is an impossible task.

As an aside, having written a lot of C, the ecosystem and modern constructs available in Rust make writing large scale programs much easier, and that isn't even considering the memory safety aspect I discuss above.