8800GTX is a different card (G80) the G92 (8800GT, etc.) are a newer revision and hence fair game...
8800GT while same die as the G92 8800GTS is a different card as well (less SPs)...
So really it went 8800GTS (G92)->9800GTS->9800GTX+->GTS250. But strictly the GTX+ is a new smaller core revision too - its only the renaming the 9800GTX+ to the GTS250 that I have big issues with as the real 200 series cards have several benefits over the G9x cards especially in quality and color processing.
While theres quite a gap performance wise between a 285GTX and an 8800GTX now adays - the 8800GTX is still a pretty decent card and can still hang with its bigger brother at lower resolutions/less FSAA - people who bought the 8800GTX originally even tho they paid quite a bit for it got a pretty decent bargin really - prolly the longest useful lifespan of any card to date.
Not really got a lot to say apart from 'I agree with this post'. I did think the 9800 GTX+'s name was silly though, the difference between it and the 9800 GTX was far greater than the that of the 9800 GTX and the 8800 GTS.