That would be true as far as being onschedule for the next 2-3yr. version to come out. The initial reaction to Vista is based most on the large hardware gap seen between the 2001 release of XP until 1/31/2007 six full years!
An average system then saw what? A Pentium II or AMD K5, Slot A(Thunderbirds oced like crazy!) compared to 4, 8, 16gb capable boards seen now. XP runs on an old boat achor with 128mb considered minimum by MS while Vista obviously being updated seeing more "extras" as well as improvements was a little too much for some older systems still in use.