Mobile part... Well, my opinion can't be really strong since I never actually owned a smartphone running Windows Phone or used one for enought time to say but... The system kinda suck. I guess the biggest problem is not the OS itself, but the lack of avaliable apps for it. A lot of cool apps (mainly social ones, but not only) are not avaliable for Windows Phone. I guess going to buy a phone that you already know you won't be able to use a lot of apps your friends with Android or iOS are using can be really demotivating.First, I think that Windows 10 will have a free upgrade. Second, you're basicly asking for them to cut out all the income they have, exceptuating the Mobile part. Well, that wouldn't be good for them, now would it?
So, making Windows Phone their only income would be self destructive... xD