Way too many generalizations in that statement to even try to break down. There is NO possible way to know if the environment your kid is in is going to maximize their potential, there are way too many factors to consider. The best environment is different for each kid, you might think putting them on the same team as that 05 player will maximize your kids potential, but what if she doesn't like the coach and doesn't give the coach everything, or the she doesnt like the other girls on the team so the is thinking about that the entire session, or you have to drive an hour to practice and she is so tired when she gets there she can't give it everything and her game suffers. There is no magic pill or team, each kid has their own path and what works for one doesn't always work for another.
All you can do is put them in the environment you feel will help them the most and go from there, but who really knows if that is the best decision. If your kid is getting better, they continue to work hard, they have intrinsic motivation, and they are enjoying the game, that is when you know you made the right decision.