AZ, you summed up my opinion very nicely. Not that I believe any one of the factors I listed is the cause for what appears to be a shortage of eligible boys (but what really is only a shortage in a very insular and picky sect). But I believe that your factor is just as insignificant. The issue is not due to any one cause alone (though if I had to pin it down on one, I’d put it to the last one on my list, and the age gap not even in the top 10).
As for other things you have said, I STRONGLY agree with you that the perception of “most people see it as a negative if the girl has been going out for a few years and still not married” NEEDS to be done away with.
Manipulating people is wrong.