"Economic system" is more or less synonmous with "Capitalism. Other social forms are NOT "systems" as capitalism is, nor is there the separation of state an "economy" that occurs under capitalism. (See ellen Meiksins Wood, Passim). The productivity of Baron A's peasants has no effect on the meaningof the labor of the peasants under Baron B. Relations (except perhaps in some controversial ultimate 'metaphysical sense) are external, not internal. And of course it is through coercion,not through any economic relation, that the product of the peasant's labor is transferred to the Baron.
Workers under capitalism recreate capitalism, not merely an arbitrary ruling class, with their labor.
In now way can the propositioiin be applied to other social formations than capitalism.
Carrol