I understand the developers. They go the extra mile by adding galaxy multiplayer, bonus content, achievements and drm free and then most gog users are saying "go away, this drm steam like bullshit, galaxy is evil". so why should the developers care? I love galaxy, i use it a lot. but most gog users seems to hate it. So i understand the developers. and i think that techland allready invested much more time in to gog than most other developers, even the free content drops like the prison heist is here on gog. techland is amazing. but they probably have the stats about galaxy usage and see "look, nobody is actually using galaxy, so no cloud save needed".
I kind of agree, when it comes to stuff like Achievements. But Cloud Saves, on the other hand, don't (usually) require that much effort to be implemented (and in fact, in many old games, I suspect it's GOG staff directly who adds them). In an open world game like Dying Light being able to preserve your 150h save is important and I still hope they think about it :)