David Pogue, tech writer for the New York Times claims (follow up here) that perhaps the reason that there are so many Wintel vs Mac computers in corporate America are because IT folks just want to keep their jobs and the viruses, spyware, and a defective Microsoft operating system help them. A corporate environment with Macs and fewer issues would, according to his logic, result in less work, a smaller budget, and a smaller IT staff.
But Pogue is missing a big aspect of the corporate world: what Visual Basic was historically, and what the .NET Framework is today. Corporate environments are filled with throwaway programs that are very specialized towards people's business needs. Without an environment like that (with serious investment) on Macs, that sort of shift is not possible. It harks back to Balmer's "Developers, Developers, Developers!"
Web applications are removing this disparity between operating systems, but I wonder if Apple sees developers as tightly bound in their corporate strategy as Microsoft does. Because they don't, and don't understand corporate software, it lends itself to the chasm between Apple computer and the business user.
ps. I'm aware of Filemaker and Xcode, I just don't think they are as good. As a thought experiment, compare how much Apple bets on these with how much Microsoft bets on Visual Studio and .NET.