I don't think anyone was doubting whether a mobile OS could be productive for some. Rather, just that for many with more complex needs, any traditional tablet -- whether it be iOS or Android -- falls woefully short of a desktop OS like Windows 8 when it comes to many critical day-to-day tasks.
@mgmueller: The battery in my iPod Touch 3G lasted about 3.5 years. It still charges and gives me a couple of hours of use, but I am going to have the battery replaced soon, not by Apple but by someone locally. It will cost less than $50 to get a new battery. The battery in my Asus netbook lasted about 3 years and I bought a replacement battery for very cheap on eBay which works better than the original. Both these devices were used daily by me. My experience with lithium ion batteries in other devices has been similar -- about 3-4 (max) years of good usable life.
I think your experience with lithium-ion powered devices may be different from most because you are a real serial "gadgetist" and constantly use new devices.
So you never run into end-of-battery-life issues. This is not said as a point of criticism but merely as observation. I have read some of your posts in the "Which one should I buy" forum with a sense of wonderment and a little bit of envy as I have neither the time nor resources to go through devices at the rate you do (but it sure sounds like fun!). For many, green issues are also a consideration when treating electronics as disposables, even if there is some recycling going on. My point is that the Surface Pro is quite pricey for such a disposable device. Microsoft should have made provisions to replace the battery.
--Pat