yk- good point. i would suggest two possiblities
1. you had more bt’s mainstreamed in the black hat yeshiva system and you had many boys from just shomer shabbos families who got inspired by yeshivos and then became ultra Orthodox, while not as common by girls. Some of the baby-boomer roshei yeshivos and magidei shiurim come from poshuter just shomrei shabbos homes.
2. today aside from the age gap,From the KIDS AT RISK we are losing more boys then girls. IN ultra yeshiva families there are more boys who do not remain like their families then girls. AND THE SAME IS TRUE WITH AGUDAH TYPE FAMILES.
Theory # 1 would suggest that we put more emphasis on being mekarev not frum or modern boys and then mainstreaming them in Patterson, springfield and fallsburg etc.
Theory # 2 would suggest that we put more emphasis on avoiding kids at risk .
i hope this gets passed on to mr. rechnitz