It is a tried and true design, I will give you that.  But could any other consumer product soldier on virtually unchanged for the past THIRTY years?  Probably not.  Take for instance, the automotive industry.  Would you buy a car that looks essentially the same as the 1990 model if there are other choices out there?  Probably not.  I was as much a fan of the Generation 3 when it came out in 1990 as anyone else in the forum, as I was the G4, G5, G6, and so on.  But, by 2014 (dovetailed with the centennial of Kirby) I expected something truly revolutionary again.  That didn't happen.  I saw prototype drawings on this very site of a totally new Kirby.  When I saw that the Avalir was just another warmed-over Generation series machine it was a bit of a disappointment.  And let's face it.  The G-series IS a dated design, and the Tech Drive DOES make the machine heavier to lift up and down stairs.  I think people would really like to see 12-inch "granny head" again and yours truly would love to see an on/off switch in the handle (as the prototype drawings indicated).  If the Kirby salesman were to come to my house, I'd pull out my Generation 3 and ask point blank "okay, so what really IS the difference?"  The answer, purely cosmetic.