Youth football at professional clubs hasn't really changed over the years in the key respects. It's a ruthless thing for a child to be involved in, demanding on normal families. The vast majority will never even be professional footballers at the end, even those who get a few first team games as teenagers. The best 13 year old may well not be good enough at 15, and a kid just clinging on at 15 might be a star at 17. Mostly, though, success depends on a young player hitting a bit of form in training or on loan at the same time as the first team needs someone in that position, usually due to injury etc.
Hence, AWB gets his chance when Ward gets injured and we don't have another right back, whereas Rak-Sakhi has the misfortune to be at the club at the same time as Olise, and even when Olise picked up a serious injury, JRS picked one up too.
In any profession a talented, hard working youngster needs there to be a job vacancy, and despite all the home grown quotas and suchlike, football doesn't naturally provide those job vacancies.
A big part of academy football seems to be about trying to iron out the inherent randomness of the above. I don't see that as possible. You can give players all the best facilities and coaching but, firstly, they seem over coached if anything sometimes and, secondly, everyone else has got those things too so it offers no advantage. Even the financial bullying involved in having half the lower domestic and lesser foreign leagues awash with so many loaned out youth graduates that you need a special manager to keep track of them hasn't really increased the youth production success rate overall. It is what it is, whatever you spend.
But clubs do spend staggering amounts on academies, as the premier league requires it. Making it pay for itself has taken on its own, often unseemly, character and practice over the last twenty years. A kid you've got no obvious use for becomes a commodity who might pay for the upkeep. That is a big change compared to the old youth team days. This leads to aggressive poaching at the upper age groups in the hope, not so much of getting a player for your team as getting a valuable assets on your books. That leads to silly offers to kids and their families. That leads to a merry go round of teenage prospects amongst the big clubs. Very few kids that come into a first team from an academy are produced by that club or are from that area. Ngumoha was at Chelsea for for years before moving to Liverpool, just like Sterling was at QPR. Most of them move around.
Hence this kid and others leaving or joining Palace. This idea that a youth player is one of our own is usually nonsense. It's a meat market.