Before I go further, are we still working off of that one study which, if memory serves me, was basically a list of girls and boys who had graduated from specific schools/yeshivas and how many of those were single/married? Aside from that not being a complete study, at best, it’s focusing on one cause of the disparity, without giving attention to other very real causes.
Also, were the study to have accounted for all factors (overseas shidduchim, baalei teshuva etc) and is correct, and “they” (still wanna know who that is) decide that the age gap is the fix, what happens with the effects of having younger, less mature people getting married on a large scale?