A paradigm shift is on the way, but...
Yes huge numbers of business desktops aren't Vista-ready and if the businesses have any sense they'll never see Vista. But if the enterprise business quite sensibly accepts that a radical change is necessary for the vast majority of their PC users, those who don't need a full function max power fully customisable individually managed Window box on their desk, just Office/Email/browse and other standard business tools, why would that radical change be to SLED or even to any similar desktop Linux, which is basically the same cost of ownership hassles as Windows, just scaled down a bit.
If corporate IT folks accept they need a paradigm shift to control spiralling ongoing costs, why would the majority of corporate desktops not be more cost effective (and more secure) if they were (whisper it quietly) thin clients or whatever one is allowed to call them these days, with the expensive kit (and expensive people) confined to the computer room where it/they belong?
Once upon a time there was little cost saving to be had by going thin; the bandwidth wasn't affordable and PC jockeys were cheap (albeit they often turned out incompetent too). Now the LAN bandwidth is cheap, but energy (to power hundreds of clients and associated aircon) isn't and (despite the hype) large scale desktop outsourcing contracts usually aren't the real answer either (does expensive and incompetent sound like a good deal?).
Good luck to Novell and IBM anyway, it's time for a change.