The problems with Vista go so far beyond minimum technical / hardware requirements that this looks to be a lame “slipstream” excuse from Microsoft...
Even many highly technical people who run high end PCs with plenty of memory and fast multi-core CPUs that jumped on Vista bandwagon and tried to emphasize its advantages early on can’t any longer ignore the bugs, sluggish performance, installation problems etc. etc.
Many of the problems go to the decision by Microsoft to start ugly call-back / WGA copy protection with the introduction of XP, especially since the overwhelming majority of the revenue they get is not from retail sales of OS but from pre-installed copies on computers from manufacturers and from enterprise volume licensing.
They started to be worried more about losing a very small percentage of revenue to “pirates” (which happens anyway) than about quality of their software. That’s usually the beginning of the end...
They are facing a bigger problem. Vista is the client for Longhorn (Windows 2008 Server), much like XP was the client for Windows 2003. They are going to have a hard time selling enterprise Admins and CIO's on the benefits of upgrading if they can't get Vista fixed. Would you risk your mission-critical environment on a server O/S whose client can't even run properly?