I like a lot of what the OP said in the beginning, but a lot of that is with the benefit of hindsight, or takes place behind the scenes.. I just read it (and a few comments) and I haven't read this whole thing, so any comment I make is probably a retread haha... (but here goes).
To me maybe the one point missing would be this: The ColecoVision was the first time me, and many of my friends UPGRADED our consoles. (I. e. Bought another console, besides our Atari). In my neck of the woods, nobody knew anybody with an Intellivision (shocking, I know) and those commercials with them ripping on our Beloved Ataris generally outraged people like me. Don't get me wrong, there were Intellivisions in the stores and Someone had to be buying them, but I am talking, within my circle of friends. We all knew 1 guy with a 5200 and beyond that Coleco Ruled! It was the one system we all had to have and the one we had to talk our parents into, Because parents back then used to say things like, "You've already got an Atari"...So that's where the compatibility with Atari games came into play. I believe I said "I'll give my aunt my Atari and just buy that adapter so I can play both!" (God I wished I hadn't done that, but that's another story).
Also we'd all saved our paper route money, etc., and were ready to buy Colecos long before they were in stores. The pages of our magazines were dog-eared, and covered in drool stains by the time they actually made it to stores.
Also I'd say Intellivision seemed along the same lines as Atari but with better graphics, Whereas ColecoVision's Mission Statement was "To bring the Arcade home", which is what everybody wanted. And they were releasing a lot of "obscure favorites", too, not just the same old thing!