You assume every piece of pirated media would otherwise be bought, this is not true at all.
It seems like you didn’t read all of what I wrote and instead only saw the last section. I did not assume that and reaffirm that piracy does in fact have victims.
While this is not the case for people that would otherwise not buy the product at all, there are still a number of pirates that would pay for something if a pirated version did not exist, and so there is an effect.