Neville- It really depends which public school you’re talking about.
I’ve taught in public schools, there is a HUGE difference between different neighborhoods and schools.
Actually, the same goes for Frum schools. Some are on much a higher level than others.
In my case, I found the level of education higher in the frum schools than in the public schools.
Again, this varies as my public school students were largely from Non English speaking, immigrant homes, while that was not the case for my other students.
On the Shidduch Crisis, the age gap seems to make sense to me, but I didn’t spend that much time thinking about it.
On the other hand, Mazal77 definitely has a point. Most girls only want a certain type of boy. We also see that working boys have a very hard time with Shidduchim.
The mostly likely reason for the shidduch crisis (other than that Hashem runs the world, which is the ultimate answer) is that it’s a combination of factors. Focusing on one factor (the age gap) may help but doesn’t solve the issue completely.