Our little firm just went through this issue, having had to replace aging Windows XP computers used by our staff and being told by our IT guy and our vendors for key software components that we use (Hummingbird for sophisticated document management, Lexis for time and billing, calendaring, etc., and others) that Windows 7 clients would be incompatible with our network setup for a variety of reasons.

This meant either spending $10K or $20K for various small upgrades using Windows XP clients or triple or quadruple that amount (or more) for doing a global upgrade to Windows 7 for clients and attendant network components. While it is nice to consider bringing everything up to date at once, no business will do this without considering the cost/benefit aspects and, for us anyway, this meant going with the more incremental changes and deferring the more disruptive ones. The hardware aspects of these upgrades are pretty modest in cost. But the expense of paying tech people to reconfigure everything gets high pretty quickly.

Thus, the point made by the article is spot on, at least from this non-tech user's perspective. I assume this will also help explain why it will be comparatively hard to dislodge Microsoft from business-related markets generally - no one wants to make radically disruptive changes on infrastructure items unless they have to.