With Steam machines providing an alternative to their OS and Mantle their API, how will Microsoft respond to this challenge to the near monopoly they have held on PC gaming for the last 20 years? Have Microsoft given up on PCs for gaming? Are they only focused on Xbox and trying to maintain their office PC business? Can Microsoft win the upcoming battle or have they already lost? Will there even be a battle? Will the likes of Steam machines and Mantle fall by the wayside?