It seems instead of XML databases, we're seeing JSON databases. True that they're far from surpassing or even nearing relational databases in popularity. Rleatoipnal databases are rather fundamental software, and there is such a vast amount of code and habits related to their use, that the prediction that they will be 'surpassed' buy something else only 6-7 years out is rather brash.
"It seems instead of XML databases, we're seeing JSON databases."
Even that one grain of truth doesn't hold up if you read his original prediction. He was talking about pretty XML-specific stuff like XPath and XQuery, and even things like DTDs and Schemas; so schema-less document stores just don't fit Yegge's story.
I don't have anything against Yegge for making such a prediction, and I'm sure he's not all that concerned that he was wrong. However, I don't think the author is being intellectually honest when he tries to twist it into a "partially right", and I do have something against that.