Another day, another "they'll never ever ever use it prediction about Windows Vista. Which is nearly identical to the stories they wrote when Windows XP came out, which were nearly identical to the ones they wrote when Windows 2000 came out, and on and on and on.
The truth is people don't buy operating systems. They purchase computers and then use the operating system that comes with it. While corporate users can (and will) specify which OS goes on their system after it's been purchased, home users won't, and so Vista, like XP before it, will slowly leach into the population through normal computer turnover. As people become more comfortable with it at home (and early adopters populate various documentation portals with advice), they will become more comfortable with it at work. Eventually someone will make the decision and the next big workstation upgrade in a company will be with Vista-equipped systems.
It won't happen overnight. It never has, and it never will. Long ago I took seriously the computer media's claims that the latest OS from Redmon was a complete flop due to slow uptake just after release. It was only after the fourth or fifth time they hailed that exact same OS as a crushing success a few years later that I realized they simply had no idea what they were talking about.