To use the style of server identity management we use for, say, HTTPS, you need a “trusted” 3rd party involved to sign certificates. This is impractical for SSH

To use the style of server identity management we use for, say, HTTPS, you need a “trusted” 3rd party involved to sign certificates. This is impractical for SSH in many (most?) cases for several reasons (SSH does support cert based identification and authentication, but there are not many circumstances where this is more practical than, or otherwise preferable to, TOFU for SSH). In fact, many people who don't properly understand SSH's trust-on-first-use system (so don't actually verify server certificate fingerprints) argue for browsers to support it as an option alongside the current certificate signing & verification regimes.