Let the dead bury the dead!
Another adage is that anything that does not grow dies. I think XML has reached that stage. It continues to be fine for what it does, but it is not now a technology that opens new doors or promotes new efficiencies. Which is just not a necessary or desirable fate.
XML is now at a much worse stage than where SGML was in 1995: standardized, adopted, stable, fit for purpose, but essentially solving the problems of the 1980s in a 1970s kind of way. And with a weeny technology (HTML) that could not possibly be considered a competitor or alternative because of its features, but sure was being adopted in that spirit.
XML was a really great subset of the SGML idea for Web backends, meeting its goals well. It is possible to make different offspring from the SGML wellspring that meet other goals. IMHO, parallel-parseability is meets a constant demand and is a good goal, and inplace parsing is a low-hanging fruit on this.
By parallel-parseability I suppose I mean non-modal or random-access parsing: that you should be able start at any point in a document and figure out whether you are in tagging or data by parsing forward until the next milestone delimiter (i.e. > or ;) which then tells you what you started in. When get this by not allowing modes, or allowing delimiter strings to serve double duty. So you can sick any number of threads onto different locations in the document and they will be able make sense of it without needing to know what went on before.
Cheers
Rick
Cheers
Rick