Re: eh???
I think the point has been missed. MS' problem is that it has lost mind-share in terms of being the only option. They are buying the bottom of the market so that "windows is everywhere." It doesn't really matter that its rubbish, they just need a presence and to be seen to there. Even if no-one buys that particular tablet, being seen in the shops has value for MS. I'd be surprised if there weren't "co-marketing funds" in play.
Its a bit like people who start out buying a cheap old ford car and as they get older and richer they move up the range. They are unlikely to switch to another brand.