People don't implement them well because they're overburdened by all of the different expectations we put on them. It's a problem with how DNS forces us to allocate expertise. As it is, you need some kind of write access on the server whose name shows up in the URL if you want to contribute to it. This is how globally unique names create fragility.

If content were handled independently of server names, anyone who cares to distribute metadata for content they care about can do so. One doesn't need write access, or even to be on the same network partition. You could just publish a link between content A and content B because you know their hashes. Assembling all of this can happen in the browser, subject to the user's configs re: who they trust.