...With mass trading and reselling DRM free games, people will pass them around and there is no mechanism to stop the previous purchasers from playing the games anymore....
Sure. But also now there is no mechanism of stopping people from playing passed around copies of GOG games. Both is illegal and both is comparably easy. So I would then demand DRM for both cases or for none.
Right, that's how you personally feel. But from a game publisher point of view, it would be yet another (extra) reason not to want to release a game DRM-free, when you have to worry about _also_ the abuse of second-hand sales, not only piracy through sharing.
From a practical point of view, it is different to actively share your DRM-free games to others, or to keep a DRM-free game to yourself while selling the "original" away. In the first case there is at least some chance of getting caught, in the latter, none whatsoever. Only in the latter case, you are the only person who knows (or can even find out) what you did.
It would be a bit of a backpedal on the DRM stance but it's the least obtrusive way of doing things.
If GOG 'backpedals' on DRM then count me as a from-then-on non-customer. I'll take my 300 games "shelf" and go home! :) /jk
Actually, GOG does have DRM in a sense. For example, I've only DL'd maybe 50 of those 300+ games.
If GOG were to close tomorrow, I could "lose" (access to) over 250 games that I have purchased.
That's not really DRM any more than that you had bough (paid) a retail game from a store, but decided to let the store keep it in their storage room, and you'd go to pick it up from them sometime in the future, if ever. Also in that case if they closed their doors, you couldn't pick up the games later anymore.
I personally don't consider the GOG game purchasing transaction really complete before I've downloaded (picked up) the game from their servers to my local repository. If I don't do that, then I am putting faith to GOG to store them for me.
There are and have been digital stores that don't offer such "unlimited" storage service. E.g. from Strategy First, at least earlier you could only download your DRM-free games from them a certain number of times (like 3 or 5 times), or maybe it was a time limit, e.g. a couple of months. And I recall some digital music shop earlier having a similar system.