This is a typical HN response: write system code in a hip, modern language - this will solve all of the problems. Which language? I haven't seen a single succes

This is a typical HN response: write system code in a hip, modern language - this will solve all of the problems. Which language? I haven't seen a single successful, commercial OS written in something else than C or C++. Part of this is the amount of legacy code, part of it is compiler and stdlib maturity, performance and predictability. You can probably get maturity with some of the existing "safe" languages, but rarely would you get any of the other guarantees. If you can throw HW on the problem, you can probably get away with SMTP server in, say, Python. But you typically can't do just that.