It's quite suprising how many can be played without the Steam client. Especially those 10+ yrs old. I dunno, have two minds about Steam, yes it's customer service is in the top 1% of all companies across the world, but draconion enforced DRMs are still down to the developers, not Steam. Steam seems secular on the subject not minding wether developers put DRMs or not on their games.
I actually feel the same way. I'm absolutely delighted that GTA: San Andreas is drm free and on Steam but I also desire other games like Skyrim and GTA V to be drm free. I know that this has nothing to do with Valve's decision but more to do with Rockstar and Bethesda enforcing drm and on top of that there's no CD available that I could find for the special edition of Skyrim but maybe I could find one for GTA V, anyway I digress. Point is, I fully agree. Although, I have never dealt or had to deal with their customer service, it is up to the developers. Even many indie games nowadays go with Steam and choose to have drm. To add, as someone has stated before, Steam is unfortunately a very big platform in terms of its population and audience. Even CDprojectred uses it for all its games and were I to hypothetically release a drm free game to the public, I would too, simply because it would reach more people.