I would imagine the bottom 50% are burnt out and the lack of playing time drives them to start giving up lacrosse for a social life, internships and work. The girls that commit to these big programs are not only owned by the sport and their coaches but they are actually told by many coaches what majors they need to take to be a part of the team. Need to keep it fun and not touching the ball isn't fun for anyone. That's why so many girls are quitting in High School.
The D1 four year rate for LI student athletes over the past 15 years is about 45%--so you do have a 55% burn rate. That is not a YJ number. I started with 2013 YJ to try and track a trend; from casual observation YJ burnout rate is considerably lower but I wanted to track a couple of classes to see if my inclination holds up.
You can add studying abroad as another reason for girls to give up the sport. When I help match a student to a school and ask "What else do you want out of college" studying abroad, internships, other sports and academics are big factors. That's where a lot of D3 schools come into play. Scholarship money for sports is not available but there is a lot of needs based money out there.
