In Soccer Laduma edition 875, Keagan Dolly said that South African players aged 18-21 are treated as "small boys." He is absolutely right, and it's a problem.
Overseas, young players aged 18 and younger are called up to the first team if they have the quality. Look at players like Neymar, Raheem Sterling, Adnan Januzaj, etc. The list could go on. Michael Owen was scoring in the World Cup for England when he was only 18!
When you give youth an opportunity to compete for playing time, it adds a dynamic to the team and forces the older players to work harder to keep their positions.
In Mzansi, the young players are told to keep their heads down as they sit on the bench, and I think this explains why the PSL and Bafana have been so stagnant in recent years. There's no youth dynamic!