system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why aren't the Rockefeller family trillionaires by now?

According to Wikipedia, "By the time of [John D. Rockefeller's] death in 1937, estimates place his net worth in the range of US$392 billion to US$663.4 billion in adjusted dollars for the late 2000s, and it is estimated that his personal fortune was equal to 1.53% of the total U.S. annual GDP in his day."

But I just looked on Forbes, and there is only one Rockefeller on the billionaire's list, and he's way down at #556 at *only* 3 billion.  What happened to all that money?
gpt
The family fortune would naturally diminish over generations because there are several heirs to divide inheritances.  JDR Sr. had 5 kids, and many of his children and grandchildren also had 4, 5, or 6 kids.  That means the inheritance would get smaller and smaller over the generations.

Then you had various Rockefeller's giving money away to various causes, spending money on extravagant lifestyles, or engaging in various business ventures that didn't pay off.