What's the difference, in terms of this discussion?
They both have a cost.
They both have a cost.
As an example, if tomorrow I invented a machine that made unlimited free copies of soybeans and distributed those copies for ~$0 to any internet connected location on earth, the market value of soybeans would very quickly approach zero.
Whether or not my machine is illegal would be quite immaterial to the laws of economics, which would continue to propagate information about supply and demand through prices so long as my machine was working.
Of course, the same is true of corn and also intangible goods like massages [0]. By induction you might claim that the story for mp3's is the same.
[0] If you find a machine that gives unlimited massages at a distance, let me know immediately
Nonono. The laws of supply and demand you're talking about only obtain under conditions of perfect competition, where goods are perfect substitutes for each other - commodity markets being the closest real-world example. By this argument, the price of opera should fall to zero because there's an oversupply of EDM and pop music. But if you want to listen to opera, chances are that you're not going to be satisfied by a new Katy Perry tune.
Who should take on that cost?
I countered that very cheap hardware would have to be free, following that logic.
Who are you to say what is cheap and what is not? Not to mention that orders of magnitude greater than almost zero is potentially still almost zero.