The problem is that we have to think if it's more important to have alibec a home grown player or to make him a better player earlier.
He is 19 years old and will be 20 in jaunary . He is not so young anymore and in my opinion he doesn't have what to learn when playing with u-18 players , at least not so much than when playing in serie b.
I think we shouldn't worry so much about the HG players. We already have in our team santon , mario , khrin , biabiany , pandev and coutinho in the upcoming years. So we already have 6 players HG for the future and if we buy bonuci and that brazilian RB we can add 2 more so we are okay (also you can take in consideration that in the 25-players squad list there are always some primavera and we need only 4 HG)
P.S Also although i think alibec is a good player , i see his future more as a piece of a transfer deal (such as aquafresca) than as a future inter player.