"The scale of products and things that are being brought to market are probably a little bit richer when I look at Sony, Nintendo, Apple and Google," Mattrick says.
Valve boss Gabe Newell recently noted that Apple is the Steam Box's biggest threat, since it already controls such a large portion of the market with the App Store. Nat Brown, the man who gave the original Xbox its name and former Microsoft leader, also sees Apple's potential to own the console game.
"Apple, if it chooses to do so, will simply kill PlayStation, Wii U and Xbox by introducing an open 30 percent-cut app/game ecosystem for Apple TV," Brown writes.
Valve's foray into the console space includes an emphasis on cheap, in-home streaming systems and Linux. Valve's PC distribution client, Steam, launched its Linux service in February and during that month it claimed 2.02 percent of all Steam users. By comparison, Mac users accounted for 3.07 percent in February.
Apple iPhone 6
Microsoft Xbox One