But if you add up all the D-SLR sales of Panny, OLY, Kodak and Fuji they would still be a distant 3rd(if lucky) place. So I would not exactly use the term "driving", more like "trying" as in trying to compete with Nikon/Canon.
Yes you are correct most P&S cameras are 4:3 ratio and Most shooters will not realize that no matter what standard size they print, part of the image will be cropped. While 3/2 would still require cropping with some standard print sizes like 5x7 and 8x10, but with 4x6, 8x12 and 12x18(which are very common) you can print FULL FRAME with no loss of image or pixels.
I assume that D-SLR buyers are trying to take their skill to the next level, and should IMO take this into consideration.
I cant speak for anyone else but I get the chills when I get the perfect shot, and would like to be able to print that perfect shot exactly as it deserves to be printed.