Earlier quoted context omitted.
>I'm so happy to read this it rings hollow from a company whose entire bedrock for existence is DRM procedures. does Steam still disallow accounts from playing more than one independently owned game at a time without special procedures?
You can now have steam families and have two members play different games from the same library. Assuming you were using two machines you could just have a second account as a family member and play both. Or do you have a crazy beefy computer and are trying to run two different games on one machine?
You still cannot play a game C from my library while I play the game A from my own library.
The only way to be able to play any game you want would be to create a separate account for each game.