Even back in the 1990s, CGI programs written in C were lightning fast. It just was (is) an error prone environment. Any safer modern alternative like the article's Go program or Nim or whatever not making database connections will be very fast & low latency to localhost - really similar to a CLI utility where you fork & exec. It's not free, but it's not that expensive compared to network latencies then or now.
People/orgs do tend to get kind of addicted to certain technologies that can interact poorly with the one-shot model, though. E.g., high start up cost Python interpreters with a lot of imports are still pretty slow, and people get addicted to that ecosystem and so need multi-shot/persistent alternatives.
The one-shot model in early HTTP was itself a pendulum swing from other concerns, e.g. ftp servers not having enough RAM for 100s of long-lived, often mostly idle logins.