Earlier quoted context omitted.
This is pretty much spot on. People usually missing the point of 'boring' because they would think of unpleasant and ancient stuff. The key value is indeed to avoid surprises. When I read WhatsApp used Erlang back in the day, I was pretty impressed. Not only the obvious things like Erlang was the forgotten secret weapon for massive concurrent apps, but also details like they used FreeBSD back in the day when there wa…
I mentioned in a comment below that a startup I worked for previously used Erlang. It was a giant headache. They initially used Mnesia as a database but it had issues (which I don't recall because it was before I joined). Then they switched to Riak which is written in Erlang, but was unstable at the time. They then used decided to use MySQL and Cassandra, but ran into issues because database drivers were contributed…
It's pretty risky for most teams. Despite Erlang was old, those ideas are both alien and novel to most people. The idioms, the patterns, and the architectures are not well explored as mainstream languages. In my personal experiences, there are also many rough edges.
With that being said, the example I raised just to illustrate that the WhatsApp founders had deep understandings of Erlang despite it was a niche technology. The same applies to FreeBSD. Those are the so-called 'boring' technologies for them.