It's very hard to prove that someone is doing the wrong thing when you invoke the term "the long game".
I can't think of any mechanism by which wealth owned by the rich (i.e. old) can skip a generation.
The only way this proves to be false is if we eventually discover the secret to healthful immortality and end up with a generation that never dies, and therefore never bequeaths its wealth to younger generations. The longer people live, the longer it will take younger generations to inherit the wealth of older generations.
The only other way this proves false is if there is a massive wealth destroying event such as war, revolution, ecological collapse, etc. such that there isn't much wealth to inherit.
The IRS can!
That said, I was talking about a generation collectively across all of society, not a specific family.
I still have my Ameritrade account from 25 years ago (then Datek, which was, at the time, revolutionary), so I'm not even the obvious consumer of Robinhood services since there was friction for me to stop using Ameritrade and start using Robinhood, but I switched all of my investment activity over to Robinhood a year or so ago (still have some stock at Ameritrade, but I don't actively trade there).
Their money is moving, because old people—at a higher rate than young people—become dead people, whose former money is then controlled by someone else, often younger.