Ceballos will never be a supreme talent. Doesn't have the brains for it. Way too cocky. Technique only gets you so far. Looked like a Madrid player tbf, probably sees himself as some sort of mega talent already.
Many of these cocky kids won't have the drive of a Cristiano Ronaldo, and will end up like the likes of Quaresma. Maybe Ceballos will be in between, good player but not Madrid starting quality. Deulofeu from Barca suffers of the same syndrome, he was once this new Messi wonderkid.
Not seeing what we should be jealous of tbf. Ceballos is getting no game time, Asensio has been nicknamed Ausensio I heard, and Isco is miles behind being the new Iniesta as touted. It would be better to take care of our own talents, because we're not short of those. Sadly, we're not doing too well in promoting them to the first team either. At least Madrid is trying, even if with mixed to poor results.
We're much in the same spot as Madrid. We also have some premiere young talents that we have to develop. The difference atm is that we're on the way up and they're going down. Normal in a rivalry so spiced up as this one, success of the other will up the motivation level and hunger for success of the rival. We got complacent after two amazing seasons like 2014-15 and 2015-16. Madrid got complacent after last season's double. And a complacent team is not a very good environment to develop young players.