Well Blackberry isn't even a thing anymore. The big three are iOS, Android, and Windows Phone. The reason Windows Phone is so behind is because it started so late, but it's been rising very quickly over the past couple years - almost in at an unreal speed. I think it's totally unreasonable for devs to not make apps for it unless some sort of contract prohibits them from doing so. The momentum for Windows Phone is very visible, and thus so is the future. I agree that it's messed up, especially considering the fact that their Activision partnership likely has absolutely zero restrictions based on mobile OS compatibility. This is either Bungie being naive or Bungie wrongfully taking out their frustration. They should know that their userbase is much more likely than, I would guess, any other to have Windows Phones, seeing that they fostered a community biased to Xbox for over 10 years.