Well all our young players can't be good enough to make it, but Marchisio has made it as far as I am concerned, and Giovinco has all the talent to. De Ceglie, maybe not. Marrone looks very mature for his age and could also be a gem. Daud maybe not, but then Giuseppe Giovinco and the very impressive Immobile maybe. It's all about giving them chances.
As you pointed out, Juve make stars. It is the same for any young player coming into a massive team, if they can make the cut they are destined to become a star by default.