The money did not just disappear. It was simply transfered to other traders. The buying power is still in the market.
there is no guarantee that the gained money will be used on leverage and that people dont take profits home
but you were trying to make the argument that USD leverage can't go up again b/c of the losses inflicted on the previously leveraged. it can and probably will b/c the winners can redirect their USD winnings to new USD leveraged positions.
edit: this is a great thread, btw, and i congratulate Blitz for picking up on this important metric.