Replace copyright with monopoly and your argument is equally sensible. Using textbook micro, the cost of copyright is clear. The copyright on Mickey Mouse raises the cost of goods featuring it. In a world without copyright, my expenditure on Mickey Mouse videos will decrease likely resulting in consuming somewhat more Mickey Mouse videos but for lower total cost and deploying some of the saved money to other goods that I desire. Hence, I will consume more of that good and a greater variety at the same income making me better off.