Piracy hurts the software developer and distributor. The hardware need the software to be useful. So if the developer leaves the platform then the hardware dies.
But, what killed the Amiga was shitty management and failure to perform in the north American market. While the Amiga (and Atari ST) were phenomenon in Europe, by the early 90's they were totally eclipsed in north America by the cheap PC clones.
Commodore also put too much emphasis on the video editing function of the Amiga platform, IMO, while letting the other possibility like games, audio, graphic & desktop editing by the roadside. The lack of accelerated graphics on the later model did more to damage the Amiga as a gaming platform than piracy did, but even then, most of the software developer had moved on to the next great platform.
