Which is fine. We have JSON and XML for data. I would rather see some cohesive standards for JSON data formats, because that is the future. HTML is just the glue between CSS and Ajax requests.
The web browser is a powerful sandboxed VM installed on virtually all Internet connected devices. And yet we a terrible toolkit for building applications on top of this VM (and I know it's because existing tools were built for hyperlinked documents and not proper stateful applications).
Also an interesting interesting topic are the different classes of these Internet applications. On one hand you have applications like Gmail, which are intended to reach a broad audience and should work on most "platforms" (substitute "web browser" for "platform" in this case). But you also have the traditional enterprise LOB application, where you may focus on one or two platforms and make that a "requirement".
Someday, it may be possible to do away with the concept of a web "page" or "document." Desktop and mobile apps aren't (generally) built in that paradigm. But if we move away from the document concept, we'll have a new set of problems. How do we represent things like blog posts, which really are more like documents than applications? How do we enable a variety of clients with varying capabilities to consume textual content? How do we maintain the useful concept of a URI, if at all? These may not be unsolvable problems, but they are challenging for sure.