We'll see. In the long run, I could see more and more people becoming interested in what Steam is aiming for — an easy, console-like experience that still offers the full freedom of the open PC ecosystem.
With Sony releasing almost all of its exclusives on Steam and keeping multiplayer behind a paywall, people might start wondering why they should keep investing in such a limiting platform.
Maybe you'll keep buying the same brand until you die, but the new generation of gamers who want to play in the living room now have a new option — and they'll eventually move toward whatever offers the best value, affordability, and access to games. You can play almost all the content from both Microsoft and Sony, and also play online for free. If the pricing and marketing are done right, the Steam Machine could start to turn the tide in the long run. They've definitely put their finger on something really interesting here, I believe.