A rewrite automatically makes things worse because you start with no code.
I figure it's one of the signs of programmer maturity, that you start to look askance at rewrites. So tempting, yet so rarely even finished let alone better.
In the case of Rust I don't believe this is 100% true given C ABI compatibility. You could start rewriting in such a way that it is integrated with the existing code and slowly, but surely tease the C out of the system.
It would for the longest time be a C program with a metastasizing wart of Rust hung off the side, impossible to get into, impossible to work with, debugging hell, compilation hell. The distros would weep.
I figure it's one of the signs of programmer maturity, that you start to look askance at rewrites. So tempting, yet so rarely even finished let alone better.