"On the Web, even if such a group of confederated webmasters existed, it requires their active and willful participation to maintain such a hierarchical style and the seamlessness of that joint interface breaks down abruptly as soon as one leaves for another page. Within Gopherspace, all Gophers work the same way and all Gophers organize themselves around similar menus and interface conceits. It is not only easy and fast to create gopher content in this structured and organized way, it is mandatory by its nature. Resulting from this mandate is the ability for users to navigate every Gopher installation in the same way they navigated the one they came from, and the next one they will go to."
Simply put, it can't reasonably be done with HTTP/HTML because it requires active management (which as I pointed out is basically a non-starter), instead of being 'baked in' like it is with Gopher.