I have a cube and I love it to bits. I still use it as my primary mac desktop admittedly because it's so damn pretty sitting on my desk but it still does the job.
The thing is that apple will never compete in a market where it'll get it's arse spanked and the pro/consumer tower is one where it just will, 99% of pc's are of this forum factor and most of them are unebievably cheaply made and shoddy. Apple just can't compete with this and I don't honestly think they should no matter how much I or any of you would like a "cube II".
Your logic is certainly sound, and you will probably be proven correct...but you know as well as I do that there are always surprises, good and bad, with Apple product releases. That was my only real point...and of course to possibly revive your long-ignored desire to own a small horse