It used to make me laugh that back in the old days of Amiga, at the OBM Arcade, above Angus and Robertson in Hobart, Tasmania. The guys there used to let people pirate their software that they were selling for their friends!
I had not quite 1,000 disks of pirated software. Having said that I had over 100 games and serious applications and supported the Amiga as much as I could at the time I was a student.
I think any game that sold 100,000 on the Amiga was doing well. Wasn't there compilations though called "they sold a million", which would make you think some games did sell a million copies?
Perhaps that was on a C64 perhaps?