Dynastic wealth doesnt last as long as people think.

If we look at rockefeller at his height he woukd be worth a out 350-400 billion dollars adhusted for inflation today (900 million back then). Wikipedia

If we check today 70 heirs with about 8.4 billion, or roughly 120 million each.

https://www.forbes.com/profile/rockefeller/?sh=32b2e618430e

While 120 mill sounds like a lot, we have to remember that 100 years ago he was worth twice what bezos is worth today. Truthly speaking probably more as Bezos wealth come from speculation investing, rockefeller had his in strong production companies that made to be to fail look small.

That doesnt even touch on lose of power. Rockefeller at his prime was more powerful than the US president if we are being honest, no one to date (or probably ever will) come to that level of power.

But yeah, inheritance at the tip top means less than you think. It goes away faster than you can imagine. Combined with the fact that inhertaince is how most families jump from low to middle to upper income, their will always be hesitants to touch it (even if they are not affected). To push that point, in my own field money means nothing, it is about connections. "Good boy club" will keep you employeed for the rest of each child's life.

You want to fight wealth stagnation fight the good boy club\connection, not I money being passed down. I can tell you I would gladly pay 1 million to give my kid a 100k a year job, with free health insurance, guaranteed raises etc... You would be a fool not to make that trade.

This also foesnt touch on the fact most money at those levels is locked up in ways that taxes cant touch.