The top 20% aren't benefitting from everyone else's system, they are benefiting by the lack of rules and control from others (essentially freedom) and their own ingenuity.

In other words, the top 20% aren't benefiting at the sacrifice of any one else... they are creating new wealth. And, it's frankly none anyone else's concern, in general, how much wealth they choose to create for themselves.

Consider if you would, yourself living on your own remote property. Suppose you have an excellent system of agriculture and infrastructure that you engineered yourself... which is immensely productive. Now suppose another individual migrates to that location and you then create rules b/w you and said person to respect each other's property. All the sudden, are you benefiting from your new society's system of rules and his agreement not to harm to you? No; you are benefitting from you own ingenuity and labor, as you were before he arrived. You are profiting from your own freedom and the use of your own mind, as you did before.