There is also the possibility that they just weren't good enough. From the looks of it, Chelsea runs a very good academy. Despite that, it is always going to be very, very difficult to make the grade into the first team squad. Apparently, Moron has been tasked to give more youngsters a fair shot, and it looks as if the boy with the unfortunate name, Loftus-Cheek, is the first. One could of course also argue that Courtois falls in that category...
Looking at our own squad now, and the caliber of players we are now looking to sign, it is going to be a tall ask for our youngsters to get into the first team squad. Not too long ago I reckon Akpom would have played quite a bit already, we wouldn't have had Sanogo on loan, and Gnabry would have been certain of a place in the squad. Instead, Akpom looks far away from a chance, Sanogo thankfully even further away, and I'd be surprised if Gnabry is with us during next season.