... single-player elements locked behind online-only walls. I think we can all agree that both NMS and Absolver have these. Whether these elements are minor or major is besides the point; they're still there.
And in my view, elements as these stop being "single player elements". They are rewards for online play which carry over into SP - which is by design in NMS, because it's a single player game in which you can activate some online "community" functions, if you choose so. Go offline, and the game doesn't freeze or kick you out or anything - it just carries on with what you currently have.
And it's not - like some people seem to think here - like "you go online and get the living ship". That would be indeed some form of DRM in my opinion. You actually do have to work for it, grinding community missions to get the required 3000 quicksilver to buy the Void Egg. HG's intention here is clearly to reward online players with something cool.
When I saw the Living Ship update I thought, "How cool, I want!". When I found out what I would have to do to get it, I thought "That's bullshit, you can keep it where no sun ever shines.". I didn't think of "DRM" or "single-player elements locked behind online-only walls". More like someone handing you candy, and when you unwrap it, drooling already, it's a flavour you really detest.
So if we treat stuff like the Living Ship as "not SP", it suddenly becomes important if it's major or minor content that is "not SP". Because some games are clearly centered around MP, with SP only functioning as a training mode, or token for "we have a game that works offline too". Games, where most of the content is intended for multiplayer, and pure SP gamers will feel cheated if they accidentally buy them.
But that is clearly not the case with NMS, I don't now about the situation in Absolver. In fact I would understand if people felt cheated buying NMS on the premise of getting an MP focused game, because it clearly isn't the main purpose.
It should, of course, always be clear what you're getting into, when you buy a game. And I agree that a game that promises offline play, but barely works in single player mode shouldn't even be on GOG. It should be made clear if some content is only available when playing online, so any potential buyer can make their own judgement if the game is good enough, even when they play offline only.
And anything any MP feature adds to the game should always be "nice to have", completely optional of course. Crippling an SP experience by requiring some online component to make it complete would indeed be a no-go for me too. But that's simply not how I see NMS.