You rightly assume that as you have a very good youth setup, and very good youth networking, you should get at least a decent or half a decent youth every once in a while. I am now in the 2017 season with my game and playing with Arsenal I have received at least 1 good and 2 decent regens. However where very good regens pops up in your game world is out of your control. For example, you say that in your game there is not one good regen in the Spanish youth teams, however in my game I have at least 6 good regens (1 GK, 1 LB, 1 CB, 2 DM and 1 ST) that I have found in my game. However the very best regens in my game comes out of Argentina for some reason, and I am not talking about Boca or Rier. They came from San Lorenzo, Newell's and Banfield. So this differs from game to game however, which adds in keeping the game interesting.