I think Cyberpunk is probably the biggest factor to blame here. Let’s be real: most of the popularity the platform gained in recent years was because PC gamers started praising CDPR as this perfect game developer for some reason. CP2077 completely shattered that perception, it inverted it even. CDPR as a whole has a negative image now, and I can’t believe for a second that the store reporting loses out of nowhere, when it was doing better than ever right before the game’s release, is a coincidence.

TLDR; GOG’s popularity came with CDPR’s very positive image, it’s going away with CDPR’s very negative image.