...not really. Take it from a musician: performance ability and teaching ability are not as interconnected as you're implying.
And on top of that, even a fantastic coach can't really do much if the one being "coached" has no interest in learning something, or in practicing what one learned.
> As long we live in a free-market society
We don't, and arguably never have. A free market is pretty difficult to achieve when you have existing players motivated to hold onto that wealth and prevent competitors from unseating it.
> social mobility in and out of the upper class is extremely difficult there.
You think it's significantly easier here? Especially with wages tanking relative to cost of living for all but the upper class, I don't see this fixing itself any time soon without one heck of a course correction. We ain't that far off from a European-style regulated society (and indeed, political discourse in the US seems to be pushing for it).
Even a low percent gain over the long term is very, very difficult. You can tell this by noting how much endowment managers get paid.
In the words of those Screen Rants pitch meeting skits: "It'll be easy, barely an inconvenience!"
The easiest and most surefire form of investment out there is in land. There's a finite amount of it, so while on local scales values will fluctuate, on an aggregate scale the value of one's total land holdings will increase indefinitely as demand increases (which it will, both from a growing global population and a growing global economy). Land ain't especially liquid, but on long-term scales that ain't really a problem.
Until we as a society pull some moves out of the Georgist playbook and tax land value, the rich will always be motivated to consolidate that wealth into land control, and will be able to hold onto that wealth at the expense of everyone else.
Let’s think on that a bit. Consider, if a parent is a musical prodigy, it’s akin to having a fantastic coach at an early age. They can teach you hard-earned insights, help you make the right choices, introduce you to the right people. This makes achievement considerably easier. It’s not as different from financial transfer as we think.
> In a century or two (barring intervention to return wealth to the proletariat) I'd expect the American upper class to get into that groove of wealth consolidation, like how things evolved in Europe
As long we live in a free-market society, I think this will be hard to do. Main reason: it is extremely difficult to invest well in the long-term. You can see this by how prized top investors are. Unless one invests well, in a free market society their wealth gets eaten up.
Europe avoids this through a highly regulated society — social mobility in and out of the upper class is extremely difficult there.
It’s certainly possible that the u.s will lose their position as the bastion of free markets — but whoever picks it up will become as powerful, and most people will start to immigrate there.