I posted this is another thread but ill repeat for this as well.
The under 20's system and to a lesser extent is the problem with NSW cup as a ineffective feeder system is a necessary by-product of the professional era.
If we are going to get kids to choose RL as their profession they have to commence that profession like every other kid when they finish school, as an 18-19yo. To do this the oldest you can have you first step in your career is at age 20.
It is not appropriate to have kids start career or study and than make them quit at age 21 or 22 to enter a fulltime squad, people complain we lose too many player at age 21, in the other system, we would lose them as they dropped off with work and study taking over amateur footy.
The step from NYC to NRL is big, and age is a factor. A bigger factor IMO is due to the fact that it is amateur to professional. It takes a few years in a fulltime training program to be ready for NRL.
The same is true for NSW cup, NSW cup is essentially no different to reserve grade (other than where they play, and the fact the sides are outsourced) the difference between the days when blokes would step up from reserve grade to first grade seamlessly is that there was a gap in talent, but not huge in alot of cases, but the training was the same or similar. These days, the blokes outside the fulltime squad, train prob 3 times a week for 2 hours plus there own fitness by themselves, The NRL team probably spend 6 or 7 times as much time training, the gap n performance is obviously going to be large.
We can put a reserve grade in and put the kids that are good enough to play Reserve grade rather than NYC, but the second a fulltime player is replaced by a part time player or newly fulltime player, the step is going to be huge.
Until there is enough money in the game to have a full time squad large enough to accomodate first and reservegrade, the gulf between the 2 will exist.
As for losing players at 21, that dont make grade, well this happens anyway, there is only so many spots available, they will move on elsewhere.
IMO the earlier we let those not going to make it move on with their life the better it is for them, they can forge a career. Those that are not going straight into first grade but may eventually make it, go into NSW cup, but enter the full time squad, and than can start to make a career as a footballer