It is nothing like the web. The web is unstructured, Xanadu isn't. The web supports all kinds of content, Xanadu is stricly textual. Xanadu documents are immutable. Xanadu is integrated with a payment system and everything is pay-per-view. Xanadu has been worked on for more than 50 years and there's still no useful demo.

I know HN has this weird custom to assume without evidence that all old failed technologies were superior (or at least equivalent) to their more successful competitors, but it isn't always that simple. Sometimes technologies fail because they aren't that great.