Not always. There are plenty games that work without the Steam libraries. Also GOG exists and very healthy with explicit no DRM policy.

And yet Steam is incredibly popular despite the DRM because it's unobtrusive. You don't get punished for replacing your computer every couple years and needing to reinstall your games.

I'm not sure I've ever heard of someone having a technical problem with Steam's DRM, I've only heard moral/ethical/worried-about-what-happens-when-Steam-disappears problems.