How many generations does average wealth last?

I like the founder of Dubai’s quote: "My grandfather rode a camel, my father rode a camel, I drive a Mercedes, my son drives a Land Rover, his son will drive a Land Rover, but his son will ride a camel." It was concerning oil and diversification of its economy. But it fits nicely with studies showing most wealth is destroyed within three generations.

Do you agree with this quote?