The problem here is that a lot of people wants everything right now. But they are bypassing that even the Galaxy Client updates use to be delayed in a lot of games. Not to mention such a singular and unique as an offline installer service relatively up to date.
If the people wants immediateness then Steam is unbeatable for now. But my opinion is that everything has a price. And if the price is a few days delay, then that price is very cheap imo.
Second class citizen in the world of videogames? Everything can go better eventualy and it is always welcome but honestly I do not mind a shit. I can live with it.

It's a two-way street for both sides. GOG doing a good or poor job for their population subset may not be representative of the whole. The only accurate way to measure user satisfaction is through aggregated data with full or randomized user surveys. This was the purpose of the recent survey. From there, they can understand demographic trends and prioritize actions that will reward higher revenues as all corporations should be operating under. The people who actively post on the forums and other GOG social media are vocal minorities, so there could exist discrepancies between everyone's views and the silent majority.

You can get a rough idea of how the market is rewarding GOG through its management board report. If they were doing that bad, would their revenue have more than doubled in 2020 compared to 2019 (p.102)? And if we disregard CP2077 sales through GOG on p.78, their revenue grew roughly +31% at ~213M PLN in 2020 compared to 162M PLN in 2019.

If GOG really is neglecting its users, why are customers rewarding such behaviour instead of boycotting? Could it possibly be because critics are overemphasizing their issues? Could it be because the majority of the customers are ignorant and in the wrong? Are these numbers inflated by the pandemic and how did they compare to previous forecasts? Only GOG and their data analysts will have the full picture of what's really going on.

i'm not the one to blame, in case you're experiencing some trouble dealing with different opinions and viewpoints or facts and reality in general.

tl:dr
So your complaint is that GOG is not offering separate update patches for the offline installers, but only updates the base installers.

I think that has been the norm for many many years already, at least for many or most games. With some games they do offer separate patches, e.g. with their own Cyberpunk 2077 and The Witcher 3.

First of all, we don't know if this is due to GOG itself, or the game publisher. Since with some games GOG still offers the separate offline patch, I presume it depends mostly on the publisher, how they provide the updates to GOG. That is the only logical explanation, why some games get separate offline patches, and some don't.

I personally don't care for the separate patches that much. To me it is much more important that the base game installers are updated, as I want to keep them for my GOG game archives. For instance with The Witcher 3 (GOTY and original), GOG still hasn't, to this day, updated the base installers, but offer "only" a separate patch. So I have to keep both the 1.31 base installers, and the 1.32 update patch, and also use them both when I install the game. I would much rather get the base installer to version 1.32, even if it meant not having a separate update patch anymore.

It doesn't annoy me much (or at all) that only the base game is updated because I tend to play single player games only after they've become stable and are not receiving much of any updates anymore. If I were to play such games (especially in-dev games or multiplayer games which might receive even daily updates), I feel using a client (like Galaxy) with autoupdate is pretty much a necessity anyway. Offline installers are more useful for complete and stable games that are not receiving updates much at all anymore.

There was never a time where GOG would have offered separate offline patches for all, or even most, of their games. Maybe you just didn't care about it earlier because GOG used to sell smaller and older games which didn't receive much of any updates. Your suggestion is utterly stupid, as there really aren't any alternatives to GOG, which would offer

a) offline installers (without clients), at least for newer games like GOG still does.

b) separate update patches to those offline installers (which is what the OP is complaining about)

So your stupid suggestion apparently is that the OP should not buy any games, anywhere. Or can you name some other digital game stores which offer e.g. offline installers and separate update patches for Stellaris and No Man's Sky? No? Figured as much.

That's just the way it is and has been for a long time. Some games for reasons unknown (or GoG doesn't disclose) just don't receive the offline installer versions of patches forcing you to download the offline installers for the updated base game all over again.
Me personally I've come to accept it (it's just not worth opening a ticket everytime and for every game this pertains to just to be told "unfortunately we cannot provide...") since as far as I'm aware only a few games are affected and the majority do get offline installers for the incremental updates but certainly can sympathise, especially in case of a subpar internet connection and being that unlucky to have all of your games fall into that category.

It sucks but as I see it there's not really much you can do about it. You can either accept it or carry on opening those support tickets under the false hope that some day the games in question eventually possibly maybe get those offline installer patches added to them.
Or you go Galaxy, which, just for that little bit more convenience is not worth it.

FTFY

Yes, it is my contention that GOG should provide offline installers for any updates that are applied to the Galaxy version. It is not true that stable games no longer receive updates. Games like Stellaris and No Man's Sky are stable, but are constantly being updated to accommodate new content. It is my understanding that GOG generates patch files automatically when an update is received from the developer/publisher. Please correct me if I'm wrong. These are the patch files used to update games in Galaxy. I just want the same access for the offline installers.

i hear, there are lots of updated and fixed offline installers for purchased steam games

there is even an interesting discussion about superiority of such installers in this thread: why gog installers suck

i'm not seeing the connection between mine and your post.

i hear that there are very good drm-free, fixed, complete and updated installers for ones purchased steam games. but only outside of the fluffy bubble of gog awesomeness. which you can always leave, to experience reality.

i heard, that cheap trolling is a sign of desperation and lack of arguments.

Welcome to the club. As someone who is a Linux user, it still makes my head tilt that they're still using the 2010 edition of MojoSetup.

I would have thought, that whether we get a patch or full installer, would be up to the DEV/PUB not GOG.

At the end of the day, going by my understanding of how things work, thanks to detailed reporting by others, Galaxy or Offline is just a matter of delivery method, as game files are essentially the same, with a few minor extras in the case of Galaxy installing in some cases.

GOG by their own account are doing extremely well, which I admit surprised me, as they certainly have many problems that are either ignored or not being addressed in a timely fashion. I guess then, that it is just a matter of staffing and struggling to keep up with it all. And of course, that would also impact their priorities and decision making.

I've had to contact Support a number of times, and I must admit they have been fairly prompt and very helpful. It seems that others have a different experience, and it may well be due to the nature of the support requested, which may well be down to staffing numbers and skills ... and time.

I believe in giving credit where it's due, and for sure GOG are not perfect and let many of us down in various ways, but as others have noted, they are still better in many ways if DRM-Free and offline installers is your preferred option. You can get some of that last elsewhere, but not to the levels etc that GOG provide.

I too hate the fact, especially now I have so many GOG games, that you often cannot just get a much smaller patch file, but have to re-download the full installer. That is really really annoying and frustrating when the game files are huge. I also hate that older versions disappear far too quickly, and even when patches are provided, you can miss them and then stuff up your update regime.

Same way I feel!

Completely understandable, you are not alone in this.

A common feeling these days including several other unrelated issues (paid DLC gated behind a client specific online check, giveaways "exclusively" for Galaxy users, etc). It does seem to be common for GOG to not produce offline installer "delta patches" anymore. Rather than endlessly re-download huge new games over & over or be forced to use a client, personally I now simply wait until a new game is "actually finished" and the patching ends before buying. If that means I have to wait a year but then get it half price, great.

I understand your pain OP. I personally stopped using standalone installers in favor of Galaxy a while ago. Having to manually download and install patches every time a game your have is updated is such a pain, it almost turns into a part-time job when you have dozens/hundreds of games installed.