Fortissimo - you don't allow for the late developers - I've seen plenty of pilots blossom later than some of their - initially - more able peers and go on to surpass them.
If that isn't an increase in ability born of practise and hard work, I don't know what is.
The difference is that the more able student often progresses faster and certainly that seems to be the benchmark for FJ selection - it is a useful metric but doesn't cover all bases.
I think we can probably also agree that flying instruction is not an activity that should be entrusted to those who have failed to make sufficient progress towards higher levels of proficiency.
yes, I concur but some of the worst instructors are those who found the whole thing too easy and then struggle to deal with a less gifted student.
Anyway we seem to have gone off-topic a bit now...