I'm not sure why you're getting upvoted. The NT base OS already runs on embedded platforms with equal or lesser power than that of any of the iOS platforms.
Are you trying to imply that the base OS is bloated? Or, are you trying to imply that the UI frameworks are bloated?
Apple didn't just port Mac OS X to the iOS platform, they more accurately ported the underlying Darwin OS to it, and added UIKit and other specialized frameworks.
I don't know much about Windows Embedded Standard (what Microsoft officially calls its modular embeddable cut-down version of W7, also known as "MinWin") vs. Windows CE, but Microsoft for whatever reason still chose to base Windows Phone 7 on CE instead of Standard, indicating that they still don't think Standard is appropriate for mobile devices. Probably they will port it to Standard eventually, but they haven't yet.
MinWin is not a "cut-down version of W7" - it was never productized, only a concept demo. Regardless though, Vista had started and W7 continued better separation of layers in NT. Maybe Vista was a percieved disaster, it was a necessary step nontheless.
An interesting excerpt (iirc, Eric demoed this in a Channel 9 video):
In October 2007, Eric Traut, a developer at Microsoft, demonstrated a self-contained MinWin system, made up of about 100 files, on which a basic HTTP server was running.[10][11] Traut noted that MinWin takes up about 25 MB on disk and has a working set (memory usage) of 40 MB. It lacked a graphical user interface and is interfaced using a full-screen command line interface. Traut explained during the demo that MinWin would not be offered as a stand-alone product, but would instead be used as the basis for future operating system releases such as Windows 7.
Wasn't it productized as Windows Embedded Standard? (in its minimal configuration)?
I must admit I've never seen this stated anywhere official, I just assumed it based on the fact that the minimum footprint for WES is 40MB, which was the same figure quoted for MinWin.
The thing is those "other specialized frameworks" are mostly the exact same ones you get on the Mac. So the accurate description would be: "Apple ported the major parts of Mac OS X to ARM and exchanged UIKit for AppKit".
Are you trying to imply that the base OS is bloated? Or, are you trying to imply that the UI frameworks are bloated?
Apple didn't just port Mac OS X to the iOS platform, they more accurately ported the underlying Darwin OS to it, and added UIKit and other specialized frameworks.