I have a large library of games I've never played on stream. a couple months back I wanted to play a game I had installed a while ago and guess what, forced always online. not from steam, but from the shitty team behind doom (don't remember which version it was), which just happened to be at the time I had a multi hour internet outage.
afterwards I figured out I had to explicitly block some network traffic to stop it from trying to force me to sign up for an account with the developer.

while steam certainly has DRM options, they are configurable by developers and afaik can't enforce an always online requirement with just steam, only though custom logic in the game or third party DRM. developers are also free to not use steam DRM.

DRM, as usual, harms the legitimate buyers.

that being said, steam still does bring a lot of value, such as their hardware developments, their work on better Linux gaming support, the update distribution through a trusted source, and various others.