Cucurella was a miss, he is ahead of Grimaldo as a player even now.
Grimaldo wasn't a miss because he was never going to be able to displace Alba for another half a decade, and we had superior talents later in the academy. But he was a proper La Masia product. Same for Icardi even if he is sob.
Olmo was another fuck up too, obviously. Thiago is the biggest muss of them all during that tenure.
But yes, the best of the best were given chances, Sandro and Munir had more than enough chance, Adama was always a clear type of limited talent from his B team days, Samper weaknesses as a player who was only developed as DLP rather than a proper pivot, or Alena who was developed as second striker than a proper midfielder.
La Masia was still a competent academy, but those were bad years fir it based on the standards it set for itself.