1. Because we both know that customers don't know what they want. Apple has proven that.
Apple operates in a entirely different hippsters sphere. Stop aping Apple. Actually, their market share isn't even all that great in smart phones and especially PCs (just tablets, and even there Samsung is eating already). Apple has record profits because of their hippster magic and totally overpriced unit prices. MS can't out-Gucci Gucci.
2. After using Windows 8 for a few months, going back to Windows 7 Aero just feels dated. No one is doing translucent effects anymore. Plus, the flat appearance on the desktop fits in to the Metro UI better. Consistency is good.
Consistency is good, that's why we have two control panels here, two task bars, and multiple GUI paradigms, in one OS. But that's OK. Aero on the other hand was SUCH a problem that it needed to be killed right away though...
3. Silverlight was a little better, but with the world moving towards HTML5 and plugin-less browsers, its days were always numbered.
No one cared about the plug-in (in the sense as a Flash-replacement) anymore. It was a hit as LOB plattform. That has been killed, good job. And no, WinRT/Metro won't cut it, because Metro doesn't work on anything besides W8, and W8 is a no go in business, thus Silverlight got stoned and WinRT is dead as well in LOB space (and WPF is on life-support). Haven't you just noticed that those people are completely without a sane future-proof client LOB tooling from Microsoft now?