Hey, I was one of the developers on the team at that time. It's been fun re-reading that write up. I learned a lot since then, and I think the whole industry has learned a lot regarding NoSQL databases, their strengths and weaknesses and how to deal with those in your applications.

You are correct that the biggest issue was that we couldn't diagnose problems when they occurred, and therefore we couldn't learn. Some of those problems were for sure "user error", others were absolutely problems with MongoDB at the time. It was a "young" database back in 2015.