Comment by internetter

It's actually mostly the same in both cases. If steam or GOG goes down, you can no longer download the games you bought. But what about the games you have downloaded? Well GOG games will work out of the box, however the steam "DRM" is really just basic protection to stop you from copying the files to your friend's computer, and can easily be removed by already existing tools like Steamless and Goldberg Emulator. So I'm not really that worried about the vast majority of my steam library. The only thing I'd worry about is spiking storage costs when steam's demise seems imminent!