I don't think you really answered my question.
I understand why you'd want to see us develop our own players and have some world class homegrown talent, because I'd also take great satisfaction from that.
The thing is nobody can ever really tell until it happens if a player is going to be good enough, and it's exceptionally difficult to get to the level required to break into a top team to get the chance. Look at Trippier, Lukaku, De Bruyne. They all spent years playing games at clubs with more modest budgets and ambitions, improved and then got a break.
I think that what is usually required to reach the best level is for a player to gain that experience. I don't think anyone would suggest, say, a 21 year old Lukaku should be allowed to be our starting striker this season. If they would then they'd be prioritising developing young players over success. Just because you play them doesn't automatically mean they become world class.
City fans aren't exactly forgiving. Look at the dog's abuse Samaras used to take. People would say what the hell is Pep doing, get him out.