We're getting a lot of movement in the store and services area. They are cheap to make, cheap to fund, and they are actually what generates profits.
In contrast, hardware is actually super expensive to market, build, design, support, maintain, distribute, channel. And a single mistake is costly because it impacts your store profits (see Xbox One, see Kinect).
If you move to hardware agnostic, you put the pressure of delivering hardware on 3rd Party vendors. You don't need to deal with supporting nvidia, intel, amd. You don't need to deal with Apple, or Android devices. You don't have this freakish amount of up front costs every 7 years. You just sell the content that they want.
Except you have to compete with all the other stores, it's the sole reason consoles exist so you don't have to. You are over thinking this.
Do you think Microsoft would release there Xbox exclusives on PC if it wasn't because of Windows?
The day you can play Forza or Gears of War on a Mac or Linux (and no streaming from Xcloud doesn't count) will be when what you suggesting might be true.