Society doesn't benefit. The people in charge of society do benefit.

Someone who has nothing likes change, because change is how you get something. Once you're a billionaire....well, you now have a couple billion incentives to keep everything exactly how it is. How it was when you made it to the top.

So it's a fight between society and the elites. Once the balance of power tips in the favor of the elites, society begins to stagnate. In some cases, because at a certain point getting more billions won't make a dent in your power the same way that removing money from the working class and making them more desperate and dependent does.