I believe you're right, but you must realize that your statement is similar to that some communists make: "real communism/capitalism/whateverism has never been tried yet," i.e. the No True Scotsman fallacy. The fair question to be asked is, "How can we restrict the state to prevent bastardizing capitalism and falling prey to corruption?" Capitalism seems to be much more resilient to it than communism, but we need to figure out how to further strengthen the state against this, because it's clearly slowly failing.