For me personally, DRM (or the lack thereof) is a core principle and I hold it above all else. Of course, that is just one opinion.
It's the same for me but the fact is we're a very small minority.
The point I'm trying to make is this one: if GOG was better more developers would be willing to work with them and more customers would be willing to buy from them.
Of course some developers/publishers will never go to GOG but for the rest, indies in particular, it's a matter of cost/benefit and if you don't see them there is because there was too much of the former or too little of the latter and in both cases it's GOG's fault.
At Steam the cut they take is 2.5 times that of EGS and still developers and publishers fall over each other to publish there. Why? The quality and features of the platform.
And EGS is at least doing
something to attract developers to their platform and if one thing doesn't work they try something else.
GOG? You can count with the fingers on one hand the number of new AAA titles that release on GOG on a year, if any. What you get instead is games like Fallout 4, releasing on GOG almost 8 years after release everywhere else. If GOG's agenda is to push for better digital rights they could do a lot better but they're just sitting there waiting for games to fall on their lap.