The graphical elements may look similar but Apple is smart enough to know that touch screens call for certain UIs/metaphors and that desktops call for others.

The UI metaphors that work for PCs don't necessarily make sense on touch screens and the ease of use tablets afford due to their "touchability" is what Steve Jobs promised when he heralded this as the Post-PC era.

Microsoft is simply not in a position to say "We agree with Apple". Doing so would betray Microsoft's current PC using customers.

So its hand was forced to merge tablets (which have been killing PC sales for 2 straight years quarter after quarter, something even MS can't afford to deny) and the PCs that have brought MS this far.

To make things worse MS made Metro which makes apps all look so similar that there is no way for developers to stand out driving some of them to other platforms.

http://www.riagenic.com/archives/889

I think it's more about the path in which they have taken. Microsoft is trying to do it all at once in a last ditch effort. Apple on the other hand has evolved into this, planned or unplanned.

Hasn't the OS X app store been a bit of a flop so far?