I think it's more that they're considered and deployed at the same scale as RDBMS--obviously oracle still has a pretty strong hold on the database world: http://db-engines.com/en/ranking
One thing that ranking does not quite take into account is SQLite on Android and iPhone. That's got to count for something, as that's a pretty massive deployment.
The reasoning in the original prediction was that O/R mapping sucks though, which is something you gotta do in sqlite. So according to that it should still count against the prediction.
According that stat counting the top 10, NoSQL databases account for 12% popularity. Given that this is talking about website mentions, job offers, twitter mentions and not actual installs that number isn't indicative of much success. 10% is actually pretty impressive but not equalled or slightly surpassed.
