Looking at OpenSSH tells a different story. It is a massive, overly configurable behemoth. The 'WireGuard of SSH' would be 1% of the LOC. It would not provide password auth, or let you log in as root with password auth, or let you use old insecure ciphers.
Maybe OpenBSD itself is better at sticking to these principles than OpenSSH. I haven't used (experimented with) it for ~5 years but read about various updates every so often.
> Normal OpenSSH development produces a very small, secure, and easy to maintain version for the OpenBSD project. The OpenSSH Portability Team takes that pure version and adds portability code so that OpenSSH can run on many other operating systems.
Unless you actually run OpenBSD, what you think is "OpenSSH" is in fact "OpenSSH Portable Release". These are very different things.
Maybe OpenBSD itself is better at sticking to these principles than OpenSSH. I haven't used (experimented with) it for ~5 years but read about various updates every so often.