Why do wealthy families hardly last more for three generations?

Thought this Quora answer made sense to the generational wealth question above..

My history teacher has a great explanation for this.

See, the first person to become rich in the family wasn’t born into wealth. The person worked and struggled to become rich. For that reason, he (let’s assume it’s a male) knows the value of money.

His son, the second generation was also probably not born into wealth. He was likely born when his father was struggling to make money, and for that reason, he knows the value of money. If he was born into wealth however, then the money is likely doomed. He will probably spend recklessly, as he didn’t work for the money, and doesn’t know the value of it.

The chances that the third generation was not born into wealth is extremely slim. I mean, the first generation likely didn’t have grandchildren before becoming wealthy. Since the third generation didn’t work for their wealth, they wouldn't know the value of money, and waste it.

Of course, my history teacher wasn’t talking about wealth. He was talking about how Persian dynasties usually didn’t last more than 2–3 generations.

It was an extremely insightful explanation for me, so I thought I should share it here. I hope you enjoyed it