"My grandfather rode a camel, my father rode a camel, I drive a Mercedes, my son drives a Land Rover, his son will drive a Land Rover, but his son will ride a camel."
Wealth dissipates very quickly especially with the nature of dilution as a bloodline grows exponentially. If you notice most inherited wealth that's more than a few generations is in authoritative states. I don't think its due to the estate tax as there are always ways to get around it.
There was a general practice that samurai funded positions for the children of their servants. By the time of the meiji restoration the number of servants a Samurai supported had grown by nearly an order of magnitude. Meanwhile the productive land remained fixed.
Unfortunately this lead to the productive assets of Japan being directed to support an increasingly capital inefficient consumption system. There is no natural reason to assume that an estate would be obliterated with time.
If wealth is large enough, then useful incomes can be maintained in perpetuity - meaning the great, great grandchildren are still living off of the wealth created centuries ago.
The latter case was common in Europe, but relatively rare in the US due to the estate tax. Historically, landed gentry were rarely bastions of wealth creation and innovation - and are usually more focused on fending off threats to their inherited wealth than creating more wealth.