Maybe if you average everything out that's true, but there are also plenty of niche developers/publishers who have had to shut down because piracy hurt them so bad. Action games and other such games with a lot of replay value may benefit from ROMs/ISOs if people are using them to "try before you buy", but with genres that people don't tend to replay, like visual novels, most will not bother to buy an official releases after they've played through it illegally. This is also reflected in how many games are passed for localization when a fan patch exists. The publishers know that will eat into their potential sales. Hell, even full Let's Play series hurt the sales of story-focused games. This is mirrored in other industries too, like how there are tons of people who blow through manga scanlations with a voracious appetite and never bother to buy an official localization of anything they've already read.