So many comments here talking about the downsides. The only reason to do a rewrite is because there are massive upsides. Maybe the implicit point is that the upside (memory safety must be the biggest), isn't worth the downside (lots of bugs to be figured out before you trust it).
I find a lot of HN discussions quickly turn into thought experiments and philosophical debates that largely forget the original topic. For the most part, I find this idiosyncrasy charming and entertaining, but it does frequently result in forests being missed for the trees.