The thing with Valve is that, outside of this monetization of online games, they’ve unquestionably had an enormous positive impact on all sorts of things in this medium just by way of sheer market forces. They’ve done a lot of great open source work, and they’ve helped create a viable exit ramp from Windows.

I don’t know about the exit ramp for a casual user, if you mean ditching Windows altogether, since that’s not really happening. But what did happen - Microsoft didn’t get to own the central position in gaming on their own platform, and Steam is a program that installs other programs uninterrupted - just to take a sense of what rights it has there for almost two decades. They had GFWL, now MS Store, integrated with XBOX, and they still aren’t mentioned as a PC marketplace anywhere besides having a monopoly on Minecraft. There hasn’t been their IE for games, and it’s awesome. I can’t say Valve and MS even compete there, but having eggs in two different baskets is better than having them in just one. Two different monopolies instead of one.