If Vista taught them something is that they can release an operating system with the worst possible reception and still make shitloads of money and lose little ground to competitors (competitors? what competitors?). Their stronghold on their traditional markets is just too strong. The way I see it, they're risking very little.
There have been many seemingly invincible companies throughout history that have fallen badly, and even disappeared, because of a simple, yet bad, decision. Think of Kodak (failed to acknowledge the digital age), Sun Microsystems (growth of powerful PCs), Sony (poor hardware/software decisions) and so on.
I have no idea what Microsoft sees as their future, but the commentary that Windows 8 has generated seems to indicate that they have alienated a very large percentage of their traditional userbase. The fact that so much tension is evident on a pure tech site, needs to be extrapolated to the larger populace that is far less tech savvy.
One wrong step and Microsoft risks everything.