Kadlin: There is nothing wrong with DRM. People that try to list problems with DRM fail to notice that DRM-free has the same issues. I had bought a ton of games on dotemu a long time ago. I probably had more games than anyone on there. All DRM-free games. Then one day they shut the site and service down. This led me to not having access to download any if my paid games anymore.
The entire point of DRM-Free is precisely to provide the ability to sidestep that problem, ie, if you're going out of your way to buy DRM-Free installers for longevity / game preservation reasons and not backing them up, then you're doing it wrong. Someone here used the example of going into a high-street store, buying a music CD and then instead of bringing it home, you leave it in the store and travel to the store to listen to it each time, then react with surprise that you lose it when the store closes with your only copy of your CD still inside vs the common sense of keeping a copy at home...
Kadlin: This leads to another issue that affects old DRM-free games that came on discs, as well as these DRM-free downloaded versions. Even if you already have the game DRM-free, you cannot access any of the new updates, add-ons, extras, or whatever it is the specific game has added or will add, unless you buy the game again DRM-free from somewhere that has it. You can make the argument that I can play the game DRM-free still, and sure, I could, but if I want any updates, new content, or the ability to run it on Windows 10, I need to buy it again. Yet if I bought it on Steam on day one, I would have had to only buy it once, instead of having to buy it multiple times DRM-free.
I don't know what games you're referring to but as someone who owns +2,000 games stretching back to the 80's, the vast majority of old games don't get updated at all (doubly so for the many developers no longer in business or reacquired by a different studio), nor can you even rebuy many of them "digitally" (eg, No One Lives Forever). For moddable games with community levels, etc, the vast majority of mods, source ports, etc, still work perfectly fine. Eg, the many mods / community levels for Thief 1-2, Morrowind, Oblivion, Torchlight, Deus Ex, etc, games still work just as well for the older disc versions as they do "digital" versions. Doom 1-2 don't need rebuying to drop the WADs into GZDoom - the 25 years apart files even CRC the same. ScummVM games don't need rebuying either to drop the data files into that. Thief's NewDark works just as well for retail discs as it does GOG. Most widescreen tweaks as listed on WSGF, work just as well for retail discs and many new digital releases rarely contain unofficial / widescreen patches or modern source-ports, so you end up tweaking the "updated" versions anyway.
Likewise, being on Steam and having DRM hardly guarantees updates. See the many examples including how Bioshock 1-2 Remastered were abandoned by devs in an appalling state still with newly introduced game-breaking bugs and save-game corruption (that the originals didn't even have). Or see Deus Ex: Human Revolution Director's Cut (that was both accidentally based on an earlier build and thus reintroduces chronic stutter plus is
visually uglier in many scenes due to being based on a console build). And by far most "premium updates" these days are endless paid-for Remasters. You own Baldur's Gate original, NWN Diamond, on Steam? Ker-ching - better open that wallet because the Enhanced / Definitive editions of many remade games sure aren't given out for free "because DRM and Steam"...
Overall, it sounds like you're mixing up several arguments and seeing it through some severely rose-tinted spectacles as although some new GOG games are lacking / lagging in updates, many games on Steam new & old alike are also a buggy abandoned mess with 'DRM vs developer laziness' clearly being two completely different issues.