From what I often hear is that they use steam users as lab rats. 1. There is a bigger test audience. 2. If they mess up a patch they only have to answer to the people who bought the game on steam. With gog they have to answer with GOG staff too I suppose as GOG tests the new build too. Maybe that feels a bit intimidating. Finally we get to the point that getting the gog build done is 'another thing on the list' of things to do and since the userbase of GOG is astronomically lower than steam's, they feel there's no rush.
Of course we do have excellent developers like Larian who do update simultaniously.

But that's just my speculation.

Yeah well, regardless of the size of the user-base, everyone still pays the same price, and everyone's money carries the same value.

And based on what elcook and Judas said, Galaxy users are the same "lab rat" material (no offence meant), as the builds are tested afterwards, and the client has a roll-back feature.

True, I think it's mostly to do with the fact it's somewhere written on a tiny piece of paper that says: "stuff to do" then they make a list of 'most important things to focus on right now' and put the gog thing on the bottom so it never gets done until way later. It's 'another thing to take care of' that has not a high priority to them perhaps? I mean I hate that notion and makes me feel like a second class customer but from what we've read here, that is the only thing I can assume.

Yes, if offering all your customers the same level of support is of low priority, it basically boils down to just treating GOG users as second class customers. Not all of the devs/pubs, some are very professional, but some others are pretty notorious.

At the end of the day, what matters to the users is the result and not the reason if/when there's a pattern of delaying updates here.

Makes you wonder what GOG could do to prevent devs from delaying or never releasing updates to GOG. Maybe add that somewhere in the contract: "If you don't deliver the patches simultanously with other platforms you sell your game on you'll get fined"? That would be pretty extreme though but it is quite the problem.

The question is does GOG need devs more than devs need GOG? We know GOG can be selective, but at the same time, maybe they don't put that into the contract to avoid scaring away certain devs or pubs...

There is this:
http://cdn.gog.com/open/galaxy/sdk/1.93/Documentation/index.html
and this:
https://github.com/gogcom/galaxy-demo-app
but it seems only developers can download the SDK themselves, so the public won't have access to the libraries and will be limited in what they can do.

And yet the community manager for Exanima claims they had long submitted the files, but the most recent patch has not been available since end of February:

https://www.gog.com/forum/exanima/exanima_in_development_faq/post39

Absolutely agree.

In fact, I am surprised GOG as a publisher does not have a contractual clause requiring the same level of support from developers as offered on other platforms.

I guess it could be as simple as making them aware of the "Steampipe" portal that GOG has.

Interesting to finally know about the testing. I wondered how that would have changed. Seems like the best way to go about it.

https://www.gog.com/wishlist/site/no_more_outdated_or_abandoned_games

In a conversation with Amy Graves a community Manager for Square Collective she mentions a big difficulty is supporting multiple communities.

https://twitter.com/ObvItsAmy/status/981869104071135232

this is a really naive idea because gog needs devs more than devs need gog.

lets assume gog has this "update games on time or pay a fine" in their contracts and dev does not deliver patch on time for whatever reason. gog then fines devs (dev probably just delists their game at this point) or gog sues the dev to force them to update the game. one or two cases like this become public and suddenly gog is known for taking game creators to the court.

as rightful as gog would be, this would be a nail in gog coffin. most indies aren't multimillionaires or have spare resources. if releasing their product on one extra platform comes with additional risks of being taken to court, then no matter how committed they are to release patches in parallel, they will most likely not take the extra risks and go with steam-only or take another store like humble.

I'm actually more in favor of some clause, more than a fine.
Like removal of a game if its version is N month older and X builds behind.
Or high discount if they're too late, or something else.

I wasn't being serious about a fine, just some clause might do the trick. Or at least bring the point up during negotiation saying that you want to provide customers an equal experience which means they cannot abandon gog.

"Money talks."

It could be something as simple as an additional levy on sales through GOG if the game version is outdated for longer than a reasonable period of time.

Put it simply - if somebody wants to sell on GOG, they should realize buyers here absolutely deserve the same level of support as they can get elsewhere. "It's too difficult" is not an excuse that should be accepted by either GOG, or its customers.