How about if you quote the stats like this; Add Mobile phone and PDA units to the first percentage and it no longer looks drastic at all. Microsoft never played in that arena at all and only started last year, so I don't know what you mean by head start.
That's not true. Microsoft has been trying to get in on the mobile trend since the days of Pocket PCs. They had some success with Windows CE back then, because there was little else available other than Palm and Blackberry, but they've been trying and failing to catch up to the iPhone for six years now.
I refer back to my previous comment; I imagine in the 70's, mainframe users would have looked down on Microcomputers as "silly toys"... Now they have all but replaced mainframes.
The difference is that microcomputers used the exact same physical UI for the end user as mainframes/minicomputers - first a keyboard and text display, and then a graphical display and mouse as well. Microcomputer manufacturers didn't invent some gimmicky new interface when the one that was already the standard was entirely adequate, so once the hardware caught up, there was basically no reason not to just use micros. If microcomputer manufacturers had gotten it into their head that they should fundamentally alter the way the user interacted with the computer, it would've been a different story.