147: If this is not enough to convince you about how correct Nasi is, take a look at Chassidic circles, where there is no Shidduch crisis, and they marry people in their age group.
Correlation doesn’t imply causation. There can be a dozen factors in the equation of why chassidim don’t have a crisis, while the rest of charedim do. Think about al the people that go off the derech, if it isn’t equal among boys and girls, you’ll have more religious girls than boys. In that case, marrying someone older will just push the problem a couple of years until it catches up.
I’ve seen this in my own community, where the average girl is more religious than the average guy.
TLDR; America ain’t China, figuring out why there is a boy/girl gap isn’t so simple.