When I was in college a few decades ago, a French economist did a study that largely concluded the same thing. I believe his study was done in the 1700's or 1800's. His conclusion was that it would take about a generation for the wealth to get to its previous equilibrium. He also concluded that the people occupying the groups would look a little different, but the economic groupings would reappear.
However, we don't have to go back to the one to three centuries for this example. The vast majority of lottery winners blow through their winnings in 3 - 5 years. Or watch ESPN's 30 for 30 documentary "Broke". It used to be on Netflix, but I saw that it is on YouTube. The examples never end of people who can spend through a large pile of money in a short period of time.