The Zune HD isn't exactly the Kin here; it's not a thing that spontaneously got pushed aside because of the preposterous mismanagement of the people involved with the project, and no one quite knowing what this thing is. The Kin was forced, not designed.
The Zune HD, I think, is something that's designed for longevity. Hell, the iPod Touch has been basically the same since 2007, with each generation tweaking its specs and adding obvious features. The Zune HD is a superlative media experience, updated and tweaked every so often with firmware and apps, and it seems like the sort of thing that's going to be useful for a long while. While Microsoft invests in Windows Phone 7, it's not like the Zune HD's going to be massively deficient in its features, aside from a few audiophile features that wouldn't make or break it. This isn't like the Kin being abandoned because it was a dumb idea from the start; it's more like the latent developments of Windows Vista that eventually became Windows 7, and at least Windows XP was still around while Microsoft got its act together.