Comment by simiones

Their job is not to write docs, it's to produce a product. The docs are a possible tool towards that goal, but there are others, with different trade-offs - such as in-person trainings.

It is fairly obvious that most of the industry believes the opposite from you here - thorough docs are an extremely expensive way of achieving good context, and as such are usually replaced with training sessions, which seem to fit most people better up to some point.