Regarding the national team there are 0% chances for Italy to even think about winning the World Cup. And I'm Italian.
I have not followed the U15 and U16 national teams, but I think that if there is talent there they can use those kids, for me those kids are very good and they are ready to gain experience at a professional level, Italy's forward line is a little higher, Daniel Maldini is a player who has a legacy behind him, I don't know to what extent he is good and can take Italy far, Totrti's son gave up football because of the pressure, so it's difficult because now the kids think about other things, it's difficult, but Serie A is going up a level and that says a lot.
The young Italian national teams are doing quite well, during the last years they reached some great achievements but the problem is that, in their clubs, they barely play for the first team, so there is no real growth, that's why more and more youngster are moving abroad, mainly to Germany but also Spain and England. I really don't know why so many Italian managers struggle to play with young players.