we would have stayed as 'main crew' with none of the responsibilities and no accountability
Ottergirl, you said it!
trouble is........ 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. They often become totally stale and disenfranchised.
Maybe a system could be introduced whereby if no promotion is achieved within 10 years an alternative job or career should be sought.