And the great grand children don't get to study because they have to get a job right away. After a few generations they finally save up enough that some kid can can study "Mathematicks and Philosophy, Geography, natural History, Naval Architecture, navigation, Commerce and Agriculture" and the cycle repeats.

Nothing wrong with the arts, but the fact is very few can support a reasonable lifestyle on it. By burning the inheritance you can produce art but nothing remains for your children. Study art by all means, but make sure you have something to support yourself on without burning up the hard work of your ancestors first.

What proportion of Americans now have the ability to study topics of less directly monetary connections as compared to those of Adams' day?

I imagine the answer to that question would be interesting and nuanced.

There were only a ~dozen colleges at the time, and women couldn't attend. 90% of colonists were farmers. I don't see where there can be much nuance. American's today have vastly more ability to study a bunch of nonsense.

So narrow the lens a bit - compare only those with the ability to attend university.

This.

If we're doing our job as a generation we are moving the focus of human education from the gross to the subtle.