As he said, given the size and complexity of the transition, one of his primary goals was to do as much of a "literal" translation first as possible. IOW, this

As he said, given the size and complexity of the transition, one of his primary goals was to do as much of a "literal" translation first as possible. IOW, this wasn't so much of a "rewrite from scratch" (which is almost always a bad idea), as "do a translation first; then do refactoring to be more idiomatic / performant later". Obviously some parts will need to be rewritten, but the lower you can keep the rewrite:translation ratio, the better. I'm not an expert in Rust, but from what I know it seems like moving to Rust would require much more rewriting than Go. The other thing, as he says in the post, is that you get diminishing returns: The Go code was 20x faster than the Python code, but the whole 7-hour operation was only 10x times faster, because at some point the external SVM calls start to dominate. So even if a rewrite into Rust could gain him another dozen percentage points in speed, it's unlikely that a rewrite into Rust would have much of an impact on his end-to-end performance; and it would almost certainly make the code less accessible.