What other professions operate within the confines of a single company to the exclusion of talent and skills outside. Pilots are professionals and ply their skills for a numerous companies across the world. If movement between companies always required you go to the bottom of the pack there would be no movement. When a consultant leaves a health authority he does not become a registrar at the next one. There is always a corporate hierarchy but this cannot and never will be to the exclusion of talent outside. If it did, then the only way to the top would be through length of service.