amok: Since the game is DRM free on Steam, then game preservation is also not an issue, anyone can back up the game as much as they want and preserve it on any device they want.
Sure, if anyone doesn't include people like me who consider Valve/Steam to be the mother of all client based DRM checks, especially if one refuses to play their games before they have made sure to have future-proofed them properly, because as soon as a client is introduced between a game and its online DRM servers, it no longer is mandatory to make a permanent fix to get that game to launch without getting an actual permission to do so from the DRM servers, as now there is the option to make a temporary client version specific hack that only fools the client to let that game to launch as long as the client is already set to offline mode and matches the version the hack is made for.
While that also makes it possible for someone to come up with a Steam emulator that should in theory be able to work with all client bound Steam games, any time a new game or a new patch to an older game requires a new version of that emulator, I would have to test that emulator on all of the games I would have allowed myself to become reliant with that emulator, whereas with permanent game specific cracks I would never face any issues with old games after installing a new game unless that new game requires a newer version of the GPU drivers or the OS.
TL;DR, For them having opened the door for temporary hacks instead of permanent fixes, I would rather fail in trying to outlive Valve/Steam than give them the satisfaction that I could not refuse playing their exclusives before there is no way left to buy them legally anymore.