Dy
1) “is only possible if the old timers marry the newcomers.”
Agreed. And some do. True if ALL 23 year olds only married 19 year olds there would be a problem.
2) ‘someone will get to the chairs before others.”
Yes some will be left standing after the first round, but if those “losers” are still standing after the second, third , fourth , fifth etc rounds. Although SOMEONE would have to be standing. It is unlikely that the same person is standing round after round after round due to just the lack of chairs
“the 23 year old boys, are unlikely to marry, say, a 34 year old girl”
True but what happened with the 40 year old boys (when they were 26 and she was 20), the 39 year olds? The 38 year olds? 37? 36? What about the 35 year olds? 34?
Are ALL her classmates married to 38 year olds leaving her no one? That just doesnt describe reality