StingingVelvet: Steam isn't DRM, in itself. It's a client that accesses a database of game data. Whether or not the game has any DRM is up to the developer/publisher/whoever is in charge of that. Not Valve, unless of course its their game. This is proven by there being no Steam hooks in Divinity 2. The version you purchase on there is not linked to the Steam client, you can run it with Steam closed, no problem.
You need to activate with Valve when installing Steam games, which is DRM. Any time you need to ask company permission to install your game and get it functional that is DRM.
DRM does not only mean activation limits.
