I don't disagree with your main point, and I think the apprenticeship model could work wonders in many tech environments. Harder to implement when you have a very migrant worker population, even at normal rates of turnover.

There is however some merit to writing down details to critical or seldom-used processes in a communally-accessed place such as a wiki. Keeping it up to date and having someone review it regularly has to be part of the process.