Oomis, we’ve been through this before: 1) those who segregate more, if anything, have less of a shidduch problem. Think chassidim.
2) What you mention doesn’t explain why more girls are left out.
As to why we have only noticed a shidduch crisis now (actually the disparity was noted at least twenty years ago), the yeshivish family barely existed 55-60 years ago, so there’s no similar dating pattern (age gap)/family size (population growth) society to compare to today’s. I don’t really think the question even starts.