Greed came long before capitalism. Capitalism is the current way to organize greed.

Wealth disparity has always existed as a result of greed, not capitalism. There have always been extra wealthy and poor. There has always been nobles and serfs. Patricians and plebians. Bourgeoisie and proletariat.

Any system of economic equality cannot exist unless there is a very tight framework around it and people designated to enforce that framework, which, ipso facto, eliminates equality, as that then puts a monopoly on a legal use of force. With a legal use of force, corruption is only a matter of time.