The good ol U S of A has a history of levellin the playin field by taxin rich folks so's they don become heriditary plutocracy.
Cep now we dont.
What happened anyways?
Here Rutherford Hayes on how much is enough from January 22, 1886:
"...We ought not to allow a permanent aristocracy of inherited wealth to grow up in our country. How would it answer to limit the amount that could be left to any one person by will or otherwise? What should be the limit? Let no one receive from another more than the law gives to the chief justice, to the general of the Army, or to the president of the Senate. Let the income of the property transmitted equal this, say $10,000 to $20,000. If after distributing on this principal there remains undistributed part of the estate, let it go to the public. The object is to secure a distribution of great estates to prevent accumulation.'
Not sure how much income that $10,000 is today, but it sure aint no millions or billions. If memory serves, the President - thas you - makes bout $500,000 per year.