I think it is a symptom of MS being a software company. They lived with the hardware they had and supported any old crap compaq wanted to put into an iPAQ. Since Apple controlled the hardware their low end hardware was much better than MS's lowest supported hardware. It allowed Apple to do more in software, and jump past where MS was. MS's big problem is that they let that kind of thing continue for far too long.

TLDR Embedded systems need tight integration between HW and SW MS doesn't have it because they only do the SW and let others do HW.