I take your point, perhaps Greaves was a bad example but on the other hand plenty of other people have made debuts at age 17 to be honest. Certainly didn’t help that he was playing with team mates who are not good enough to put in any kind of performance themselves let alone protect the new boy.Greaves was a genius level talent. Scarlett isn't.
He should be getting experience at a lower level, not his fault he's being asked to play in the first team before his time.
It's probably doing more harm than good.