They still are sometimes - I was fiddling around with Steam and in my "Library" I accidentally clicked a dropdown which displayed "GAMES" and "TOOLS" as options - clicking "TOOLS" filtered on a bunch of interesting SDKs and Dedicated Servers (DayZ, Arma 3, Half-Life, Just Cause 2, and such - loads of which I don't even own or play). It's not perfect and it's far from comprehensive, but there are some games which offer this still