The fact that an age-gap + population grown causes a problem for girls has been documented in many societies (India, for example) and is accepted as fact in many academic publications. This isn’t a chiddush.
However, there are many other factors at play: a) What is the age gap in our community? b) How much of an ameliorating effect is the fact that more boys are born than are girls, c) How many “extra” boys die per year?, d) How many of the extra boys suffer from disabilities that render them, to some extent, “unmarriageable”, e) Is there a greater OTD rate among boys than among girls, f) Do more girls become baalei teshuva than do boys?, g) in general, is it more important for a girl to be married than it is for a boy to be married (i.e., do we prefer a boys shidduch crisis over a girls shidduch crisis). Regarding the last question, the Gemara says that women have greater desire to get married than do men.