I think the ideal training program for a young basketball player (in season) would be a couple of team practices, an individual training session, and 2-3 days of mixed shooting, running, agility, and cross training. At least one or two days per week of complete rest other than maybe a little light shooting. Then tournaments every second or third weekend. For at least one third to half the year (off season) more body work, some pick up games, and maybe a very light game schedule just to keep the rust off.
But this is impossible, not because of the coaches but because of the parents. If you give a player a weekend off, and the player is any good, the parents will hook her up with another team as a 'guest' player. And they really hate the idea of an off season. If your team isn't playing travel tournaments, they will switch their daughter to a team that is. On the other end, parents often don't care much about practice attendance, skill development, or physical development. Why? Because that stuff is boring to them.
Overall, if you want to understand everything that happens in youth sports, it's mostly about keeping the parents entertained. The enjoyment and development of players is secondary.