<question>Who</question>
"question":"Who",
To me, this does not seem like a win that's worth much, especially since it's likely to shrink considerably even with naive fast compression.
Furthermore, as messages grow in size, the explicitly named closing tag actually kind of starts helping.
Both of these syntaxes have their annoying quirks, for sure, and I understand you really dislike the closing tag; that clearly doesn't bother many people.
But regardless of personal preference, I'm really skeptical any of this really explains json's relentless path to replace (most) xml. Other reasons, such as the extreme wordiness some xml apis chose, the poor implementation of namespaces, the problems with embedding arbitrary data (in particularly control characters), the inconsistency between attributes and elements, the lack of support for numbers, the lack of (conventional) support for key-value pairs - all of these surely played a much greater role than a fairly limited syntax issue.
And it's not even like json is without impractical quirks; lack of comments, the ban on trailing commas, and the need for quotes in object-keys spring to mind. Yet those don't mean json is likely to die out soon - even though even javascript itself from which it is derived doesn't suffer from those (anymore)!