>What could have been done differently to end up at a good solution?

Simple, not having a user agent from the start.

Ideally a URI would always just return the exact same webpage. Except it became necessary to be able to update them which broke this assumption, and eventually the need for some kind of authenticated session spawned all kinds of mechanisms that definitively killed off URIs as Uniform Resource Identifiers.

Perhaps if we were to do it all over we'd have a uniform method for authentication, and maybe even the possibility to refer to past versions of a page. Alas it was not to be.