you are missing my point.
One last try with an extreme example.
If it wouldn't matter at all (trainingtime) then a 10 yr old all atrocious player with high potential would be best according to what you just said. After all he has a lot of years to train.
But the trainingtime you have to put in him to get him at that age where he is a great player for his age is still valuable.
Crunchy! If you eat fast enough