If Windows finally starts to crater noticeably, I predict Apple will provide a version of OSX+n that will run on the hardware that Vista won't run on. This will keep that older hardware in use.

True, Apple makes money selling hardware, so it would seem they don't have any incentive to support these old junkers. But they want prefer selling high-end, high-margin kit. Getting cheap bastards -- and younger users -- used to using a Mac will prime the upgrade pipeline.

Besides that, it's not like PC hardware doesn't hit junk prices within a year-and-a-half already.