Games have always tried to implement DRM, whether it was requiring a game disk to be inserted or a funny graph to be consulted or a word on a specific page from the manual to be entered.

You know what happened when you lost any of those physical assets before the rise of the Internet? Go buy a new game.

As someone who feels that it is a moral imperative to pay for creative works or forgo them, Steam is just fine by me.

Steam didn't bring about DRM in games. Games not listed on Steam still have DRM, and generally have much more restrictive DRM than Steam. DRM isn't even a requirement for selling on Steam. Some games (though not many, I know Bastion is one example) will run without Steam, and Steam is just used for updates and achievements.