“nearly all the boys who ever marry are married after their third year”
Correct.
Now please explain how if over the course of 3 years, 300 girls have entered the market and three hundred boys. You say that after 3 yrs almost all the boys are married to the girls that entered during those three years but yet many many girl are still left. My math isn’t great. But it would seem that if 280 boys are married than 280 of those 300 girls should also be married.
You can’t have it both ways. All the first year boys getting married and all the second year boys getting married to the same first year girls while maintaining that we continue to have many girls become second year. It just doesn’t add up.
UNLESS there are more first year girls than first year guys.