> A lot of 12 factor sounds like common sense to people who regularly ship stuff.

In 2023, yes. A lot of the 12 factor methodologies became table stakes in the modern cloud era. Back when this was written "cloud" was not nearly as ubiquitous as it is now, although we were certainly headed in that direction. A lot of the comments here are viewing this through a 2023 lens and forgetting it was written in 2011.