Giving the size and age of the C ecosystem, the number of bugs is not really a valid argument. We will see an increasing numbers with Rust as Rust is increasingly used. I also do not question that Rust solves some problems. It just solves them rather badly and at high cost while bringing new problems.

I looked at firefox code a decade ago, it was a complete complex nightmare mix of different languages. I can see that this motivated starting something new, but it was not a clean C code base (and not even C).