Is that chart for academy players though or just players like Lukaku, De Bruyne, Salah etc who were bought young and sold on but they were never academy players? Genuine question like as it's not that clear but I think you're probably getting young players bought and put into the first team squad mixed up with young academy players who've come through the ranks, of which there's not many.
I remember an article about 5-6 years ago about Chelsea's academy since Abramovich took over, it had cost something like £65m to set up and fund yet not one player (at that point) had managed to establish themselves in the Premier League squad.
Yes that is for all players to be fair, but I donít see a huge difference between kids who are brought in when 10 and kids who are brought in when 17 like De Bruyne.
Iím sure Abramovich does want youth products to come through and flourish (donít we all!), my issue with it was the idea of Chelseaís set up being portrayed as having failed and being against Abramovichís wishes, when really its a deliberate strategy that is working very well.