Do you work for MS?
To answer your first question, I have to confirm something... I though Windows 8 was meant to be cross platform etc, in other words isn't windows 8 supposed to be a replacement to the Windows Phone OS? If not then I am guessing it is meant to share with WP8, so why would it improve WP7.5s marketshare?
Oh and Windows 8 will not be bundled with every tablet, people will still be using IOS and Android on those.
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Personally I don't see any advantages of moving to windows 8 on a desktop or laptop until I can use it with a touchscreen, and if MetroUI can't be turned off people using a mouse are gonna get pissed off (perhaps it can be turned off, but the last video I saw of it working [before Christmas] the Metro interface was defaulted to every time you go to the 'desktop')
Don't get me wrong, if I had the money I would love to buy one of those all in one touchscreens to act as a desktop, then maybe have a TV I could control with a tablet device in the living room and a smart phone to travel with... and having it all able to connect through Windows 8. 'twould be awesome. But it is going to take some time for Windows 8 to penetrate people's home devices before it will start to influence people's decisions about smart phone OS. You seem to be assuming a few weeks after W8 releases 90% of computer owners will have upgraded. I'm not even sure Windows 7 is beating Windows XP yet in terms of use (though it is probably mostly business computers holding it back, which won't have as much effect on what smart phone OS people choose... but it should still help show how slow the adoption rate is)
