Let's try some BBZ type of projection.
You have various type of talented young players.
We have
1. Players who are talented but need nurturing, mentorship, they need a platform in which they will develop, and they need a manager to do it. This means they are not that supremely talented to make it regardless of these things being present. You have here a good portion of the Liverpool players (except they started to transition to category no. 2). Many such players on Madrid, Bayern, and even Barcelona.
2. You have young superstars. Young Mbappe, young Ronaldo, young Messi, young Neymar, young Iniesta and so on. A select group of young players who basically are so rare that they will basically change any team they are part of. They simply have the X factor.
3. You have also the talented players who lack the mentality, the professionalism, to make the next step regardless of conditions from 1). Here you have basically someone like Quaresma, and players who were absolute wonders early on, but on the way they lost themselves.
The percentage of talented young players is something like 38% - category 1), 0.01% category 2), and the rest is 3).
Imagine having such a crap program, and almost no vision, as to only need players from category 2) that can come in at your team and change things up. That's Barcelona today.
De Jong, Arthur, are probably 1). People think they are crap because they are not 2).