Pirate Bay is not representative of the pirating scene, it only has the “tip of the iceberg” most popular stuff, and even then missing a lot of it. For a better view, check BTDigg… but even that is missing data from all the private trackers where more dedicated people are keeping the more obscure stuff, not to mention the not-torrent networks, which is where most of the scene is. Then you have private datahoarders who keep their stash off-line, but can make a copy available if you ask nicely.

You could probably find any game ever published, even multiple version releases, if you contacted the right people.