Are you sure about them being removed from the platform? I purchased GTA: San Andreas before the shitty remaster came out, and I can still download it. It is no longer available/purchasable, but I still "own" it. Do you have a better example, as I haven't really heard of this happening before?

But yeah, all the other points you mention are valid. GOG is better in this regard, but their platform is nowhere near the level of Steam in terms of user experience.