Previous discussions here convinced me that there is some basis for height due to current exceptional (Baruch Hashem) growth of the community and age differences. Numbers add up. The “fault” is, of course, on those same parents who have so many children – so they have themselves to blame 🙂 Also, modern public health and medicine that enables those babies to survive – and Medinos of Israel and other artzos that partially support those babies and keep sholom in the world so that boys are not drafted into dangerous wars…
There are though differences as birth rates and age differences are different at different sub-communities, so “modern” crisis may be 10%, while Neturei Karta 30%.
I also wonder whether drifts between and out of communities differ by gender? I presume girls are more conservative (and have less time by being younger) to change the community, so this can also contribute. For example, if some charedi boys decide to go work and start feeling second-class among their own and move into more modern circles, this will decrease modern crisis, but increase charedi.