Ideally, yes. But top clubs nowadays buy players as soon as they show promise. Best examples are Arthur and Dembele Barca bought. Arthur played 40 games for Porto Alegre and Dembele something similar for Dortmund (one season only) before both got snapped up by Barca. You would let them develop a few years in the best case, but it happens quicker nowadays. When they come calling, rarely does a player say no. I have read in the summer that they fear someone else could buy De Jong or De Ligt, for example Spurs or Bayern. Then they would have to pay double or triple the amount in the coming years to get them from these clubs.
As for the hype, Social media and twitter are a huge part of that. Every player getting linked to these clubs gets hype, especially Barca. They are hyping up De Jong and De Ligt to be their next Cruyff and Koeman with avatars/photoshop and gifs all over their timeline