Well, Valve did say if they ever close shop they’d offer all your purchased games as downloads without DRM. Not that it will ever go that far.
Even in the cartridge days if you played on PC you had to download patches from the developer website… which as you can guess nowadays is no longer available. There was also SecuROM which bricked several games as the activation server no longer exists.
But sure, if we go all the way back to Super Nintendo and Nintendo 64 then those games will survive the apocalypse. Many PC games even from that time wouldn’t (at least not fully patched and you might scratch a disk).