That's a great idea, thanks, hadn't thought of it before. CDP at least provides access to the older version of The Witcher 3, that should be standard practice as well.
I've known I have an old system for a while (and it's not like it was ever top of the line) but it's weird finally seeing everything release outside of my playable range. Mortal Kombat 1 really shocked me though, because like I said, MK11 was only 4 years ago and not only can I run it, I can run it basically maxed out, and yet MK1 I don't even meet the minimums. You'd think they'd at least give us the gimpy switch assets as an option on PC for lower systems.
Yup, learned the hard way over the years - when official updates are coming that can break mods; new version or expansions increase system requirements; new update version ain't as good as old for whatever reason; new version breaks old saves; etc etc.
Example - GTA San Andreas Steam-update a while ago broke saves and removed songs, so I also have Retail version installed (Non-HD update and also has OG songs still there). It can be a pain to downgrade SA properly, using Steam-version; especially since an even newer update on Steam added Rockstar Launcher junk.
Thing is - CP 2077 is big, so you're probably gonna need like 200 GB open, if you're gonna have 2 versions on same drive. Or, of course...just squirrel old version over on another drive and don't have Galaxy ever find that old-version.
Sometimes I'll even re-buy games - just b/c I want to make it easier across the board for running multiple versions or whatever; especially if another version's dirt-cheap and/or the game ain't huge. Sometimes Steam's a pain w/ forced updates, so having a GOG version can help as Galaxy has a feature to disable all updates too; I just take updates on Galaxy when I feel like I need them. Sometimes some games on GOG have OLD-version as extras or you can legit degrade to an older version via Galaxy.
Galaxy downgrade can be useful for like Two Worlds II, for example - as WorldMerge Mod don't work on new-version (after any version of 2.0, once Call of Tenebrae DLC came out); so I keep one version before 2.0 (for WorldMerge Mod) and a version with 2.0 (for Call and newer DLC's). Also, System Shock 1: Enhanced, newest version has stutter issues that is NOT in the previous version - so, best to just downgrade.
And usually, I have like multiple versions of Vampire: Bloodlines installed - one from retail modded like crazy w/ other mods (like Wesp Plus Edition Unofficial Patch) and GOG Version w/ Wesp Basic Mod (since GOG version ships w/ that version of the mod).