Not one player from the fabled La Masia, in the current squad, is under the age of 23 and that's Denis Suarez. They had a very unusual set of circumstances with Messi, Iniesta, Xavi and the like, a bit like the rags in the 90's. Everyone keeps talking about it because it happens so rarely.
Like you, I would like nothing better than seeing a few of the academy players integrated into the squad but, first and foremost, we've got to be challenging every season. Once that is happening the pressure to keep buying 'off the peg' should hopefully, be reduced.
You completely misunderstand why Barcelona's youth policy is successful. It's not successful because they had Messi or Xavi or Iniesta in the academy.
It's successful because Montoya, Cuenca, Tello, Dos Santos, Bartra, Munir & Sandro got 391 appearances between them before being moved on, because Sergi Samper, Rafinha, Suarez and Roberto have 279 appearances between them. That's 670 appearances for players who are well below world class since ~2010.
That's why they produce Xavi, Iniesta, Buesquets, Pedro etc. - because they give the players chances, and some take off. Some just become decent squad players, some just take a few dozen appearances and aren't good enough, but they give 2 or 3 players a year the chance.
Those legendary players didn't go into the team and immediately boost it, they weren't thrown in under sterile risk free conditions, they weren't given chances when the pressure of winning was off.
If you say you want youth to come through when the pressure is off, what you're actually saying is you don't want youth to come through, because everyone knows the pressure is never off. Winning the league won't decrease any pressure on Pep or the upper management, in fact the pressure will only go up, because you're expected to win as champions.