We've had a lot of bad luck with our young attacking talents. Deulofeu, Adama and Halilovic all turning out to be awfully flawed one way or another.
In the last 15-20 years, only Barca's level attackers from La Masia were Messi (who is more a luck than some kind of a rule) and Pedro.
Plus, there were some ok guys who managed to make their name in other clubs after Barca B.
As mentioned before, La Masia is okish and good in creating awesome and okish midfielders for Barca.
In terms of attackers, we will always have to rely on buying proven world class attackers.
So, people shouldn't expect too much even from current La Masia attackers or 90-95% of attackers in the future.