I worked for a company where the average employee had 20 years experience at their job. There were a lot of employees with 30+ years at the same job. They were around long before ISO training requirements were created. Obviously we did not require an artisan (it was a complex process) of 30 years to have a step by step procedure. The (valid)arguement for the Quality department was, what if the artisan of 30 years leaves, through vacation, early retirement (that did happen), promotion, fired, etc... What would happen to that process? This was not a valid arguement to the worker of 30 years since "he was from the old school" and didn't miss any days!
So we compromised, the job description defined the minimum amount (years) of experience needed to perform the experienced artisans position. We let the employee decide how much experience was needed, which gave that person input in the creation of the new system and a chance to pad their ego. They usually said that their job could not be done without procedures with less than 5-10 years experience, which gave them security. They agreed to train backups, and eventually found it easier to write procedures.
I was always in favor of accurate josb decriptions approved by responsible management. You wouldn't bring in raw materials that didn't have specifications, why would you bring in new employees (the most valuable resources) without defined specifications in the form of education and experience.