I don't think the quote intended to imply that Capitalism propagated a myth. I think the quote intended to imply that the subject of the myth was Capitalism.
E.g. suppose I said "One of bowling's most enduring myths is that wearing a bowler's hat improves your score". Does this imply that a cabal of bowlers spread propaganda? Or simply that the myth exists within the bowling community.
E.g. suppose I said "One of bowling's most enduring myths is that wearing a bowler's hat improves your score". Does this imply that a cabal of bowlers spread propaganda? Or simply that the myth exists within the bowling community.