--> So it stands to reason that publishers may well decide "why bother with the time, effort and expense of a 'proper' GOG release of our game when we can simply release the game on Epic, have it be sold through GOG Galaxy and still target the majority of their userbase?"
If GOG's "cut" comes out of Epic's with no renegotiation, then there may be more direct financial reasons for publishers to not do a proper GOG release:- A.
Epic version of game sold on Epic Games Store = 88% publisher / 12% Epic cut. B.
GOG version of game sold on GOG / Galaxy = 70% publisher / 30% GOG cut. C.
Epic version of game sold via Galaxy = 88% publisher / 12% cut shared between Epic & GOG A+B
= Publisher needs to maintain 2x separate releases and 2x upstream updates / patches, plus pay developers to recode GOG-specific integration work (eg, Galaxy Achievements) A+C
= Instant +25% more profit to publisher, plus publisher only needs to maintain 1x release resulting in half the work with each update. No extra Galaxy integration work needed.
If A+C becomes more popular than A+B (for obvious reasons), then publishers wanting a dual Epic + GOG release will start demanding it by default for future games. If GOG says no, or if GOG ends up dividing the publishers up into two "deserving vs undeserving" groups which have to pay different fees to GOG based on GOG's "curation", it may well p*ss off publishers enough they may well just leave GOG completely and go A only. After all, Option C = GOG users are happy to USE the Epic Store version (whether they go through GOG to buy it is a separate issue). And the Epic Store game itself will still show up in Galaxy due to "client integration" making buying Epic Games from Galaxy vs buying Epic Games from Epic completely irrelevant to the "all my games in one place" thing. A+B+C
= Epic version gets released on Galaxy then converted into a proper GOG release later = Extremely unlikely as on top of paying devs to support a second stream of patches, Galaxy achievements, etc, it would also require publishers to voluntarily take a pay cut unless GOG matched the same 12% deal as Epic (which they can't afford to do).
The primary mission of GOG right now seems to be summed in two words - Confused Divisiveness - first dividing its community up into 2nd class offline installers vs Galaxy, then DRM-Free vs "sort of DRM-Free", then dividing publishers up into who is "deserving" enough to pay 12% (Epic on Galaxy release) vs who is "undeserving" and gets charged 30% (a real GOG release). GOG really haven't thought this through at all that if they think they can award some publishers 88% cut and lower support burden through "curation" and everyone else will continue to be "happy" with 70% and higher support burden, yet in reality they are opening the floodgates to publishers wanting a dual Epic + GOG release all pushing for that 88% deal and GOG ends up with either 1. less income than ever, or 2. a lot of p*ssed off and alienated publishers rethinking their long-term relationship with GOG after being charged 2.5x more for doing a "proper" GOG release than their peers for doing a fake GOG release...