I agree, but I feel like pointing out that any game that was distributed without DRM or that was successfully 'cracked' by pirates can also be found on archive and therefore might be carried over to future generations. Physical media isn't the only way.
The real risk, IMO, is live service games that don't function at all without the server being online. There are games where fans have reverse-engineered and made their own server, but there are definitely ones that will slip through the cracks and be forgotten too.
There are three categories of live service games for which fans have reverse engineered a server:
1) The server doesn’t do much other than connect the players, and most of the logic is either client-side or trivial.
2) The server contains a fair bit of game content (such as drop and spawn rates, maybe even NPC dialogue) and the community has done extensive packet captures while the server was online.
3) The server binaries were leaked at some point, and everyone agrees to keep it a secret and pretend they’re doing a clean-room reimplementation from packet captures. They are, but against the leaked server, not the production server.
Having worked on a few of these projects, you’d be surprised at how many of the successful ones are actually #3.
This is problematic because we can’t rely on data breaches for game preservation.
I agree that live service are the main threat, but even so you should not have to rely on pirated software to keep using something you paid for. Also not all game ends up being cracked