mmorgan
I would speculate that the adoption of Win 8 is more complex than what you have outlined. I think it's true that MS was losing out in the marketplace to the smartphone 'revolution' but I would speculate that this was because smartphones fulfilled a need to for the average consumer to be able to email, surf the web and surprisingly, call people. All at a favorable price point, in my opinion this cut into what had been a cash cow for MS.
Meanwhile, back at the office, there was less of a need to do the upgrade to OS and productivity applications. I work in the IT group for a multi-discipline engineering firm. We haven't even completed the upgrade to Win 7 yet (we're at about 85%) and I'm unsure if the our primary engineering apps even support Win 8. In my opinion it isn't that Win 8 is a misguided direction it is that the market has shifted and the implementation of the markets direction does not match the business goals, The market has gone to consumers, not businesses. This is fundamentally different from the previous upgrade cycle path which was also part of increased capacity in processing power. We are primarily a CAD based company and CAD requires a lot of processing power, certainly equivalent to a DAW and quite possibly more so.
I don't question at all the proposition that much of what was previously done seated at a desk can be done (to some degree) in a mobile mode. I do that all the time. I have the same emails fed to the desktop and the smart phone. I certainly check messages away from the desktop, and value the ability to give a quick yes/no response, which is often all that is needed with an email. But for anything requiring a more involved response, I wait until I have access to the more powerful platform, if waiting is practical. I do not believe that the average mobile-only user can do an effective job at complex tasks using only that little device. And I offer Twitter as Exhibit A. You can find all the snarky one-liners you ever want to see there, but you will have to look long and hard to find anything of real substance.
Because the mobile devices have offloaded much of the light duty from the desktops, the desktop sales numbers are down. That isn't because they have failed to keep up with the latest UI. It is because they are becoming more specialized -- still being essential for complex tasks, but not so essential for a lot of simple day to day things. I think Microsoft has fundamentally misread what people want in their desktops and it killing what would otherwise be a stable, profitable (albeit smaller) revenue stream for them. In my view, it is a horrendous blunder, and Ballmer should have been gone several years ago. It is the wrong idea, plain and simple.
I am not saying that the desktop UI should not continue to evolve. Of course it should. But radically switching to a completely foreign concept, giving users no time to evolve into that -- a new "paradigm" that doesn't even make sense in the desktop space, is a colossal mistake, and Microsoft is paying a very dear price for that. That price was worth paying when moving from DOS command line to Windows GUI. But Metro is a different deal. They took a mode of operation that was serving users very well and really wasn't is need of any revolutionary change, and put a gun to the head of their users. Change everything or else you have no options. The users have spoken.
Microsoft is backing off a little with 8.1, but too little too late, I believe. Windows 8 is off to the dustbin to join Windows ME and Vista. Every other OS release for the past 13 years has been an unmitigated disaster -- and "unforced error" to borrow a sports term. These fools just refuse to learn their lesson. You only get so many chances.