iOS was originally cut down for performance reasons. Then large parts were locked for security - especially carrier network - security.
Performance isn't an issue, but carrier security is. And I don't think mobile users are going to be happy about having to download a constant stream of unlabelled Windows updates.
Where Apple went wrong was with iTunes, and especially with the horror show involved in getting information into and out of an iDevice. If you have an independent collection of music and books, it's just too clunky.
I bought an Android Galaxy Tab recently, and not only is the screen better than the screen on any iPad, getting books into it is trivially easy.
Either way, I'm glad Cupertino has competition. There's been more than a whiff of complacency from that part of the world in the last year or so, and I hope this makes Cook and Co sit up and stop taking the high end laptop market for granted.
Although gotta say - I'm still amused to see the MS presentation design following the Apple/Jobs presentation style so closely.
Maybe both companies should just merge? That would be interesting...
So, to me Apple are out if the game. It will not be Apple who will give us the mobile workstation quality OS in a pocket device that can hook up to a screen around you and allow you to work like you do today on your desktop.
Edit; that said; bring on the competition. I would buy a Surface Pro just to experiment if it had more battery life. I hoped the 4 would be (a lot) better in that department but it is not. So then I'll just run my MBP with El Capitan instead for now; http://i.glui.me/1GuUc4H
CE was also the base for Windows Automotive.
The OS was way ahead compared to what else existed out there, and I do think it got some stuff from OSX, but now it's clearly on a very different state rather than merging/