Ghengis
I agree that generalisation forces 'special cases' and it sounds as if your acquaintance is certainly one such person.
However, at 22 he has gained 3,000 hours of professional experience, but not acquired a lot of life experience. This may or may not be a limiting factor in his particular role, but in my area of expertise, which is not aviation related, there is certainly a high premium paid for experience as well as qualifications.
I guess that if I added up my working hours, say the last 10 years would be relevant at an average of 1500hrs per annum (somewhat higher than your average ATPL due to no hours cap), then my life experience (a fuction of age) and 15,000 hours relevant work experience, brings a premium of about 90-100% over a younger and equally qualified, but less experienced person.
It would be interesting to run an experiment to see if there really is that (or any!) amount of measurable difference in the value given and received by knowledge transfer, but there must be a reason that sophisticated organisations pay nearly double the price and I suspect that trainee perception plays a great part in this. If they perceive me to be "expert", then they are more likely to follow my advice, which of course is precisely what their company wishes them to do.
Extending this principle of perception, if a customer of a FI perceives (a) inexperience and (b) ulterior motive in working towards an ATPL, this possibly explains some of the emotions and thinking on this thread.
I don't think that it is arrogance in every case Ghengis, but just people 'norming' against their experience of society, where the authority figures and experts do tend to be the 'wrong' side of 40!
Have you ever noticed that newspaper articles tend to quote age - e.g. "Final 3 Greens, age 47, is an opinionated b@stard who presents polemic as reasoned argument." What is the relevance of age in this context? So why is it so often quoted?
The answer is that age and experience are unconsciously linked in society's thinking and are used as a benchmark for decision making - perhaps inappropriately.
Personally, I believe that PPL instructing is more oriented to algorithms than heuristics - e.g. the majority of learning is about "if this happens, then do that", rather than solving unstructured and messy problems.
Of course, there is some of the latter and it is very important (e.g. , WX diversion planning) but IMHO the majority of the course is about learning by rote - and that is no bad thing, the good practices learned become instinctive.
So one could hypothesise that the life and work experience of instructor at PPL is less important and that 275 hours is more than adequate for this role - I had a low hours instructor, working towards the airlines and he did a super job in teaching me how to fly. His attitude was totally professional and I never doubted his commitment to my success.