In furtherance of this point let’s take the article’s author at face value $50m inheritance @21% is $39.5m...not bad! But let’s now be a little more realistic, the family has two kids and not 1 so $19.25m per child - now let’s say that parents died at 85 and had their kids at the age of 30 so the kids are 55 which means they can invest their money for 30 years, and let’s say they invest it in a nice vanguard balanced fund, their after tax annualized return would be 5-7% [1] If we use the past 10-20 years as a guide (this also assumes you live in a place with no state tax like TX or FL). Now inflation is 2-3% so we’re making 3-5% real which means that over our 30 year investment horizon we could expect to increase our wealth between 2.5 - 4.3x if we don’t spend a dime... let’s be real someone with that money is going to want to enjoy at least some of it! So let’s say they spend 2% (or ~$400k/year real) now that 3-5% real is 1% - 3% real or 1.4x - 2.5x the original corpus - now they pass it on to their 2 kids, they’d be lucky to pass along the same amount they inherited - spend a little more along the way, have some bad investments, get a divorce, have more than two kids and your heirs are almost guaranteed to get significantly less than their parents ... Sure they’re still rich, most rich families are in decline once the money’s been made...it may take several generations, but eventually their progeny is back working...

[1] https://investor.vanguard.com/mutual-funds/profile/performan...