I think people in LI have better choices than we do in MD. In LI the public school leagues are so good, you have a lot of competition and opportunities for the high schools to provide informal training or even informal teams in fall or in indoors winter seasons. I've also seen some LI publics doing summer tournaments. Generally speaking, kids in MD are either in an expensive day prep to get access to that, or needs to try to find it somewhere else. And club lacrosse is a bad somewhere else so far as training and development are concerned. A lot of kids just tune club lacrosse out in high school because with the prep dropouts from club, the level of play goes down fast. And even the prep kids aren't playing or training much in summer. 2 events with 2-3 practices ahead of the events might equal seven days on the field in June, July. I know kids do showcases (which ar even more of a joke) but that just isn't sufficient to get better.
It is no wonder to me that the success rate of seeing the field and doing well is much higher for LI kids versus other areas, including MD.