It may be more established but it suffers from a similar problem: some people continue choosing it for the wrong reasons, such as "our backend is in JS, most of our devs only know JS, and it's easy to just dump objects in there", which is an abhorrent reason for choosing it, and will end up biting you.

IMO this would be a case where if you're dealing with a relational domain and the engineers really don't know SQL you should either (a) rethink your hiring policy or (b) spend one of your innovation tokens in having everyone learn SQL.

(I have to add the inevitable disclaimer that I actually love JS and do not want my words to be misinterpreted as a cheap dig at it)

Does mongoDB still use math.random to select 10% of errors and only report them, while 90% are ignored? Or did they correct this "behavior"?

Um, even if it's mature technology that doesn't negate the costs of operating two different databases which is a large part of what the original presentation is about.