Even the DRM-free ones? Because with those I'm not getting any EULA.

Yup. On Steam, each license is actually a subscription with a one time access fee. Splitting hairs until you understand that as a subscription there's a lot more control over what you can and can't do with the files that way.

I'm quite interested in this, since I amassed quite a bunch of steam games (damn you bundle buying Greed!1! )
But reading this article to the end, it says the guy got his account reactivated.
So is there any case where steam really permanently disabled an account of one of its users full of rightfully purchased games (licenses) or is it just a myth and in reality it just never ever happens? (ie. not an account full of freebies + G2A games or even fraudulently gotten keys)

oh god! what the hell are you doing in your freetime!

Given the absolute and rampant abuse of "Steam Family Sharing", on VALVe's own subforum on their own website, I can say whole heartedly that VALVe does not give a flying fug. They've got your games and trapped the players, they've got most publishers trapped as well. But neither think they're really trapped, or don't care. the few that do care come here.

Piss off the moderators by saying they're using the tips and help forum as a oubliette to hide unwanted posts (which they do) and you'll get a forum ban. Point out they're still using it as an oubliette gets me... I mean you, a permanent forum ban.

But to loose your account. Dressing up as a big mac and punch Gaben in his face is about the only way now.

Its more hassle than its worth for them to hand out account bans. VALVe knows they're on thin Ice with how they work. If they start banning accounts like the good ol' days then the chance of a law suit gets higher.

As for account bans, I know of one GAben worshiper that lost his account after he tried to give it to his son. Yet he still defends Steam and how it works.
Freetime, thats his chat roulette income...