These XML vs JSON talks are tiring. They solve entirely different problem domains. XML is for documents and JSON is for data. It is not the fault of the XML spec that programmers go nutso on its usage outside of its problem domain.
I don't understand your point. Documents are data, are they not?
Documents are semi-structured data, that is they are a mix of text and structured data elements put into a structured hierarchy.
problem is in that 90% of applications does not need to process mixed-content documents, yet because XML was the new cool-and-interoperable-solution-to-everything it got to be used for anything and mainly for things that are only simple structured data. Probably because you can abuse it for that and as a bonus you get lots of tools (like XSLT)