Plenty of developers have shipped out a game they believed to be bug free only for the players to discover hundreds of missed bugs on launch day.

You are mistaken if you believe that developers believe the games they ship are “bug free”, and I would bet that many of the bugs you think are “missed” are actually already known on an internal issue tracker somewhere. But those bugs were determined to be shippable. And again, that’s not specific to games, but software in general.