You wrote: "CS4, CS5 and CS6 can still be activated and used."
What sold me on CS3 is that it speeded up the making of vast composite images I have to do that in my line of work, which is biomedical research. I was annoyed when I had to learn Photoshop 7.0 after years of enjoying Photoshop 6.0. I can use this software for artistic purposes and also to make my baby pictures look better!" Eventually I figured out: "I don't have to use Photoshop just for science! I was a painter before I became a scientist. Scientific journals are picky about how many "figures" you include for publication.
May I tell you a story? I spent years using Photoshop 6.0 just to put photographs and drawings and graphs and data into one publishable JPEG. Thank you John! And I apologize for my grouchiness.