Counterpoint: budget re-releases of games (e.g. ‘Platinum’ on PlayStation) were often an opportunity to fix bugs, or sometimes even add new features. A few examples:

• Space Invaders 1500 was a re-release of Space Invaders 2000, with a few new game modes.
• Spyro: Year of the Dragon’s ‘Greatest Hits’ release added a bunch of music that was missing in the original release.
• Ridge Racer Type 4 came with a disc containing an updated version of the first Ridge Racer, which ran at 60fps.
• Super Mario 64’s ‘Shindou Edition’ added rumble pak support, as well as fixing a whole bunch of bugs (famously, the backwards long jump).

Those are just off the top of my head. I’m certain there are more re-releases that represent the true ‘final’ version of a game.