dantruon... the economies of scale argument can only apply to the same product... i.e. PS3 has a break even/cost neutral point that is COMPLETELY independent of X360 or any other similar console. We have no idea what the cost neutral economy of scale is for either console therefore your estimation is most likely false.
Just to point out with a real world example, the economy of scale that yielded a profit for Nintendo GC has existed for several years. By designing a cost effective console from the onset, Nintendo has reached its necessary economy of scale to yield a profit even though it has sold less units than the Xbox 1.