Couldn't Microsoft sell PCs and laptops in their stores though? You don't have to sell only Microsoft products.
Brand loyalty is one thing, but attacking other people who feel differently is nutty. I love my Blackberry 8750 but have nothing against people who slather over their 3G iPhone (like a co-worker of mine). In fact, I like the smartphone innovation the iPhone has helped accelerate. But it can't do email like my precious BB.
Dell and Gateway have tried too. And have you seen the business in Sony Style? There's a reason the Apple Store works, and I just don't think Microsoft will be able to cut it. That said, I wish them the best of luck. I'll be supremely interested to see how things go.