Well, this strategy is really interesting, but I think it has a few disadvantages:
1. This plan only works with PG/SG players;
2. You develop slower that the teams which train a player for a short term.
The second point is wrong,because train a player for some season allows you to grow every week,so you can improve faster than users that train players for short time,because they had always to start to train their young player from lower points,so losing competitivity and money(because of the worse results) in the short period,and when their players became better,they had to sell again their trainees so restarting the cicle