Can anyone think what Microsoft is doing now with the Surface is "risking it all?" Because to me, it looks like yet another round of Microsoft's answer to absolutely every new development: Hey, I know, we'll put Windows on it.
Here's what "risking it all" would look like: Finally declare Windows is EOL. Put it in maintenance mode, no further updates. First step after that would be to work on an entirely new OS specifically for tablets and phones, without a hint of the old Windows UI anywhere. Then think about what they're going to do next for corporate clients, home PCs, and so on.
Yes, it would be massively painful in the short term. But Apple got through a similar transition just fine, when they ditched Mac OS 9. And if Microsoft does not do this, it's just a matter of time until some other company does it for them.