The catalyst to bet on the Steam Machine was Windows 8, which had some elements that made it less gamer friendly. He adds that Windows 10 once again became more gamer focused, and says there's no longer a need for "Steam Machines" because they gave Microsoft a kick in the butt:
“So that’s where the partnership between Valve and Alienware really initiated around the Steam Machine concept,” he continued. “We said: ‘Hey, we can’t lose Windows as a gaming platform.’ We had to take matters into our own hands because we couldn’t rely on Microsoft. So we did that, and we started pursuing the path that we did.”Full details at PC Gamer.
The potent mix of Microsoft’s seeming ambivalence towards gaming, and the nonetheless rising PC player base, meant that companies like Alienware (which is a subsidiary of Dell) and Valve needed to act. But just as the Steam Machine concept was starting to gain traction, something else happened.
“Valve ran into some delays with the controller, and while that was occurring, Windows 10 was being released,” Azor said. “I think Microsoft learned a very valuable lesson – a lot of valuable lessons – with Windows 8 and tried to correct those with Windows 10. It’s more gamer focused, I would say. Every subsequent release has focused on gamers. Although their execution isn’t perfect, it’s definitely improved compared to Windows 8.”