Most of the regular contributors to the discussions here appear to have at least some technical knowledge in the computer field and even those who profess allegiance to Microsoft clearly have some experience with its products. In contrast the overwhelming majority of business PC users have no personal interest in the personal computers they use at work.
The average inventory or accounts payable clerk, for example, will not know what brand of PC is on her desk, what its operating system is, or why a megabyte is an insult to a gigahertz.
There usually are, however, some user staff who do know and care - and they usually care a lot. These are the local go-to people for PC problems; often acting as ex-officio IT staff who no longer bother with their real jobs and, instead, spend much of their time ensuring that management doesn't change the technology basis for their local social prominence as computer experts.
Organisationally the clerks and other white collar workers who don't know and don't care about PCs also don't participate directly in battles over IT control. Instead they're like the poor and uneducated during election campaigns: everybody talks about their importance and value, but the the side assuming their allegiance actually depends on their continued ignorance and dependence for its success and therefore uses nonsensical bogeymen like a threatened "return to the green screen days" to keep them in line -and then leverages their horrified, but fundamentally misinformed, response to those threats to prevent the other side from even talking about making any kind of significant change.
In the IT context what the PC zealots embedded in user organizations depend on for their social roles and freedom from the job they were hired to do is more the continuation of the status quo than of the actual technology - and what defines that is a single consequence of twenty-five years of corporate attempts to implement the client-server paradigm in a useful way: the enormously complex desktop device used to do a very simple job.
Take a close look at what most of the PC users in larger organizations do and you won't see power users creating complex documents or finding brilliant ways to use Excel in corporate strategic analysis -such people exist, but there aren't many of them. The vast majority simply use their PCs to work with centralised applications on centralised data - doing CRUD on schedule, inventory, customer, or financial data; generating shipping, work order, or other process control documentation; or just switching information from one user to another.
What the PC does for those people is run a complicated GUI client to a centralised application - at high cost and with low reliability. They're not empowered by this: in fact, they're generally willing to live with it only because they're told, falsely, that there's nothing better. There are people who are empowered by the PC, but they're not found among the majority of users; they're the PC proponents: IT people who would otherwise be selling used cars and user group employees would have to go back to the relative of obscurity of their real jobs if the organization adopted a dramatically simpler desktop.
Notice that maintaining general user dependence requires continual, but constrained, change - not enough change to threaten the PC proponents, but enough to minimize the stabilizing value of institutional and individual learning among the general user population. I.e. the general user's ability to learn, however slowly and reluctantly, means that the people who depend on user ignorance for their positions in the social heirarchy cannot allow the desktop to stabilize.
Thus if you're getting pressure to install Vista - you can bet it's usually not because Vista's better; it's usually because the people whose voices you hear raised on the issue depend on product churn for their socio-economic well being.