TL;DR we had some buggy C code and fixed the bugs then rewrote it in Rust and wow we didn't have as many bugs... that we already fixed.
Rewriting something is not the same as the first effort. Try green fielding see how long it can she develop it once you already had the first basic C code it's pretty trivial to convert it to rust most of the time especially just using other libraries.
And imagine that. You fixed all the bugs in the prototype and the second rewrite didn't have as many bugs. That's his nothing about the second versions language it just says you fixed all the bugs in the prototype.