Before talking about the shidduch crisis, there is a problem with the theoreticians of this shidduch crisis. They are too married to their own creation and closed off to hearing any opinions or analysis that doesn't fit their narrative.
If the issue was a few percentage points of additional girls, how would that explain girls not getting calls? Getting married is 1:1 but calls/dates is not.
The underlying data source is terribly flawed. The numbers are only approximately related to our population, and with no attempt to adjust for events between birth and adulthood.
The number of unmarried girls at age x should be reconcilable to the number of excess girl births, but it is not. Not in numbers or in percent.
I can (and have) continue to list dozens of counterpoints to this birth rate theory. This has been going on for >10 years. The key takeaway is that it is not a satisfactory source of causation from a statistical view. You'll notice there are never any statisticians involved, only laypeople saying statistical words.
There is absolutely a shidduch crisis though, and IMO it has 2 causes:
1) personal choices, no need to elaborate
2) number of girl cohorts in shidduchim vs number of boy cohorts. This is a vastly different problem from a slight imbalance in the birth rates, and very much connected with the personal choices issue.
As long as the focus is on the wrong problem there is not much chance of developing a good solution.
I don’t think you need to be a statistician. Basic math should suffice. You are forgetting the cumulative effect. (Calculating this on the fly so correct me if my math is off.)
Let’s take Lakewood births and do the math. Let’s assume we are starting from a clean slate and that every single boy makes it through the system and marries one of the girls.
If we take the girls from 1998 and the boys from 1995 (the 3 year age gap), after every girl gets married there are 75 who don’t have any boys for them (526-451=75)
For the 1999 cohort it is 59 extra (590-531) PLUS the 75 girls from the previous year.
The 2000 cohort is an additional 139.
2001 yields an additional 145.
2002 girls cohort yields an additional 216.
By 2003 not only are there an excess 282 girls (922-640=292), there are still 634 girls left over from previous years so there are actually 1.556 girls vying for only 640 boys. ( In the chassidish world boys marry girls older than them, it’s only the Litvish where boys have their pick that it’s rare.)
And Lakewood of the 1990’s accounted for only a fraction of the frum population. Multiply the numbers times 10 and you get an idea of the magnitude of the problem. 15,000 girls vying for 6400 boys. The only way you are getting a date in that kind of environment is if you somehow stand out. Money. Yichus. Parents went to the same bungalow colony. Chance encounters. Etc. a perfectly average girl with nothing to differentiate herself is likely going to find herself being relegated to the thousands of excess girls. Is it any wonder that thousands of girls aren’t getting dates?
And this model is actually far more rosy than things are in actuality because it starts with a clean slate, ignoring the cumulative pile of unmarried girls already in the mix from previous years. And we are assuming a perfect world where every boys is marriage material and actually gets married to one of the girls in the pool. Any additional boys that are unmarriagable due to falling through the system etc. only takes what is already a calamity and adds to it.