there are 100's, perhaps 1000's, of crew who have done 15 - maybe even 25 - years, who have no chance of becoming csd or even a purser. Some of whom are very competent.
Many of whom have no wish to progress. They are happy with what they do, are comfortable with their choice and are very good at it. Knowing yourself and being comfortable with your own limitations is a rare attribute! I know of someone who became a Purser, did all the preparation and passed the interview but when it came to doing the job for real did not like it. To quote her "I used to look forward to coming to work and now I don't", she went back to 'main crew' and was much happier.
It is a conundrum that is not an airline one alone. Motivating and inspiring staff who have no wish to progress any further. I remember a group of managers from Finnair coming to Waterside on a fact sharing mission on exactly that project. I am sure there are retailers, offices, Police stations, hospitals, etc all considering the same thing. It is not a lack of ambition which makes one or two of our crew such a pain in the proverbial!