I'm pretty sure that in the case of windows phone, it's over. It's terminal now, I don't think there's anything that MS can do to revive it. Even UWP, it's not going to drag the mobile platform to where it needs to go. I thought there was some optimism a month ago, with some interesting announcements, but that's gone, and it's just going to regular run of the mill bad news all the time.
This last case of selling MS's remaining nokia assets may indicate a convergence in their mobile business and narrowing their strategy, but honestly, I don't think it's a winning strategy. They're just constantly flicking the reset switch, and that can only happen so many times until everyone gets sick of it.
Good news now is that we might see a decent nokia android phone.