You've forgetting the third option (there's always a third option) - pirating. It's DRM-free, which will continue to run despite the DRM vendor disappearing or there's a fault in the backend or network connectivity or your account is disabled due to any number of issues.
I don't tolerate DRM, but I'm not an open-source zealot either. I love me some closed-source software that's nicer to use and more functional than some of the FOSS stuff out there. But I just can't accept DRM. You say we accept DRM on movies. Who's we? I pirate movies because I don't want DRM, but if I stick with a DRM-free diet I basically miss out on everything that's part of modern society culture. Companies HAVE to compete with DRM-free media since pirates will happy provide it if they don't.
It's amazing how many people seem to think Valve will be around forever. I don't have that level of faith, so I want to know that the software I buy can be run without having a mandatory requirement to access (either continuously or very occasionally) some server somewhere to verify I'm able to use the software I paid for. If I can't pay money for something that I can control access to myself, then I don't pay. I've read too many cases of people not being able to play anything because their Steam client's fucked up and offline mode doesn't work during a network disconnectivity, whereas with DRM-free content, it would. AND WE ACCEPT THIS AS NORMAL?!?
We've fallen too far I think in accepting this as reasonable.