That said, you're right that there's something a little off about accepting other people monitoring what you can do in your own home with your own property.
That's why GOG has a good chance to provide a strong competition and actually change the landscape for the better. Comfort of usage with no DRM would be a clear contrast to other services and can eventually prompt them to ditch DRM as well.
GOG's going to have to out-feature and out-customer-service Valve, because the Steamworks DRM is transparent enough that most people are not going to see that as a valid selling point.
GOG think otherwise. And GOG users confirm that. Visit GOG forums and find out for yourself. Unsurprisingly, many GOG users don't use Steam at all. Whether that is because of ethical or practical reasons doesn't change the fact that they don't. GOG know what they are doing and know their audience as well.
You keep bringing up "limits" and "preventions", yet I am at a complete loss to describe anything that Steam meaningfully does along those lines. Even the incredibly broad fair use arguments that could be made against other systems don't work here.
Actually, come to think of it, not every game on Steam uses Steam DRM (aka Steamworks).
While technically, some games which don't require the client to run can be manually copied to back them up, Steam forbids using them in the TOS if you don't have an active account. Now imagine a scenario when you have hundreds (or more) games in your library, and such kind of DRMed service just goes bust. Having no access to all those games would make all the downsides of DRM so much more clear, though it would be quite late already.
Either way, Steam is clearly geared towards DRM approach. In contrast, GOG doesn't require anything like that, and neither enforces anything like that. Once you bought some game, you can back it up all you want and install / play it regardless whether your GOG account continues to exist or not.
However, I find that the client offers enough on its own (the in-game overlay, mostly) that I'm more annoyed when I can't get it to work with a game. I have re purchased games I already owned on physical media and other ways to get the Steam integration (and I'm not alone there).
Steam going bust, in addition to being really unlikely, would be a mild annoyance at best, since bypassing it is a simple matter of replacing a DLL.
Feel free accepting a local police department dedicated solely for policing you located inside your own house. Or for example, imagine yourself with ball and chain, or some kind of electronic device attached which limits what you can do in your own house as if you are a criminal. Others find it completely unacceptable. That's exactly why it's police state like and it seems that you don't get the point.