As stated in the Xbox first party thread, Xbox's bread and butter is multiplayer, that's what they have built their brand and platform on and that's the audience they've cultivated for 10 years, as the industry moves toward GAAS it's a natural transition for Microsoft versus Sony and Nintendo. To your last point, they do have software to push their hardware and that's third party games, the same games that already pushes their hardware (the top selling Xbox One games backs this up).
Software wise Grand Theft Auto, Destiny, Call of Duty, Battlefield, Madden, FIFA, etc. Has done more for Xbox One sales than Halo or Gears ever will let alone their other exclusives and that's not a knock on Microsoft's 1st party games quality. That's just the reality of the current landscape.