If in doubt about the historical context of the "www" subdomains: This was, when dedicated services were run on dedicated machines (or rather, dedicated network

If in doubt about the historical context of the "www" subdomains: This was, when dedicated services were run on dedicated machines (or rather, dedicated network interfaces). "www" was just a default appellation (much like a well known address on particular services) for a server running W3 services. I don't see, why there isn't a use case for dedicated service domains anymore. (Not everything is WWW.) There's no magic to this and has never been. (The magic is in the port number as encoded in the protocol portion of a URI.) Regarding the context of the example, all this is about navigating and about communicating how to navigate. Real live addresses tend to be much more messy, but they are bearable and users have been able to operate them for what is now several centuries.