I think whoever drafted Darko Milicic or Hasheem Thabeet would disagree. :)
I only have one 20 y old, yet I'm training three guys. You need to understand that players can be trained after their 21 years. In fact, they have to as players under 22 will never be dominant in D1 and rarely enough to fight with opposition.Before selling some players recently, I had 7 out 11 players trained in my team. Currently, they are 5 out of 7. Proof that I trained i think.
Also the NBA bring in nearly finished players, here we get very rough talents.
Derrick Rose.