Having gone to public school (poor but bright in the old assisted place days) I can confirm that, though the advantage of much more games time and generally being better fed is a big factor.
Worst I came across was playing an U16s match and on the opposition was a 6'5 man, clearly capable of...
While I feel for the victims in this I can't be the only one thinking "does this mean there might be two more tickets to Ajax available"? (I'm guessing the son can't go without his **** of a dad)