One word: Minecraft.
If MS releases a really fantastic, special, version of Minecraft and link that with features of Windows 10 on tablets and desktop/laptops, the phones will fly off the shelves into the hands of all the kids currently going crazy for MC. Then, as is usually the case, the devs will start work, the parents will want in on the 'I'm cool' thing and sales will increase.
It worked with Apple with the iPod. As for Google... That's cool NOW but people are actually buying SAMSUNG or HTC devices... consumers don't see the item as 'Android'. That will eventually hurt Google. I hope.