Sorry, I disagree, in my experience its the type A gymnasts who burn out the quickest - my daughter was 'the odd one out' in a group of 4 as she was the only one not type "A". And she is now the only one still doing gymnastics 18 months later.
DD's coach loved the other girls, they would repeat a skill over and over until it was perfect, put pressure on themselves at competitions (and quite often benefitted from this) BUT had a hard time learning new skills (it had to be something that could be perfect straight away), far preferred to do the same thing over and over, liked winning (one girl stayed in the same level 3 years as she would win every year!).
My DD, by comparison, is a very different gymnast, she loves learning new skills, is an awesome all rounder and is very relaxed in competitions. After 4 years of competing she worked out that she quite liked winning and could use that as a focus for her gymnastics as well as having fun. She is now a senior gymnast (equivalent USAG Level 8), and although physically talented, she does not have the 'type A attributes' which her coach so highly prizes of 'perfectionism'......and is undervalued because of it.