That's not the case here. Apple will lose 2/3s of a quarter of iMac sales, maybe even a full quarter. That is significant.
It is only significant if those folks buy other stuff. If the vast majority simply wait and buy in the subsequent quarter there is no long term significance at all. For those who speculate on Apple stock it may be significant. But that has nothing to do with running the company. The company isn't run for the benefit of short term speculators.
If you think that would have happened under Job's watch OK. I do not. He made blunders, but not like this.
This isn't even a blunder. The month of November isn't even over. Even if the 21" launches on December 4th and the 27" on Januarary 3-8th it isn't that large of a deviation from the announced timeframes.
1. Steve being involved in design is not the point. I never said it was a bad design, so you are completely off topic there. Cook announcing them for sale when the manufacturing wasn't yet perfect for full-on ramp up is.
A design that is difficult and unpredictable to manufacturing would exactly be the point. It can't possible be a good design if it cannot be made in volume well and predictably.
2. You cannot go to the Apple Store online or retail and buy a new iMac. Some 3rd party resellers have inventory still, yes, but who is going to buy one and near full price knowing they've been discontinued and an all new one w/ modern connectors has been announced? (Take a look at iPhone sales once mere speculation of a new phone hits the general Internet news feeds.)
iPhone sales drop but not to zero. Secondly you seem to be myopically focused on the quarter. Even if apple hit the Dec target for the 27" model they'd still be hurting for the quarter.
3. Speed Bump: Bump up the Sandy Bridge proc in each model. Top of the line can get the 3.5ghz. That's what a speed bump is. You are suggesting a major overhaul which is what the new iMac is, but Apple can't push out.
So 3.5 GHz from 3.4GHz is a significant difference? Not really. That isn't going to be seen as significant by the vast majority of iMac users. There was far more moaning and groaning when the Mac Pro 2012 models came up than cheers for joy.