Time4Tea: Starting to sell DRM-ed games will lead to GOG's downfall anyway, since DRM-free is their only unique selling point.
DRM-free is not, and has never been, GOG's unique thing.
There used to be DotEmu, there still are stores like FireFlower, etc. There are DRM-free places.
What made GOG unique was the combination of these ideas:
1) Focus on older games, bringing back classics from "abandonware".
2) Selling only completely patched games with all available content.
3) Worldwide prices, no regional ripping off.
4) No DRM, everything can be freely used once downloaded.
The only remaining old principle has been DRM-free, and there have been signs of them slipping from that too, like multiplayer games. Now, this Epic thing, which probably will turn out to be an epic fail, means only giving up on the last remaining thing of a set of principles that a decade ago used to make GOG unique.
But it wasn't about DRM only.