Thats not what I said or meant actually.
Of course the team knows what is happening but ARM wasn't sure. Something as big as ARM transition was not being on strict timeline as things would happen that would make Apple postpone it by a year or so. Maybe ARM was meant to be announced last year with the DTK being A12 or who knows when. Things were taking a bit longer or complications arised and it got pushed to this year. We don't know this and I'm sure Apple was fairly open in their timeline about that.
That brings me to iMac redesign. You really think that redesign was only for ARM and not Intel? I seriously doubt that as the planning ahead would be crazy to focus on something that I'm still developing and am not sure about till it shapes up better.
Most likely scenario is that iMac redesign was (and is) planned for Intel but with AS in mind. Think of it this way, current gen iMac runs hot and fans kick in because of the limitations etc.
Now, Apple redesigns that for Intel but thinking about AS too. So they will have a great redesign that will give them even more benefits once they use it on AS. Why? Because Intel sucks now but AS will also have fairly big TDP so having more room will only allow Apple to go crazier (remember 2013 Mac Pro fiasco?).
In other words, AS will have cooling and will have many cores etc. to match/surpass Intel + AMD performance.
Don't think that AS will be magical miracle. It will be awesome but it will still have TDP etc.
So, Apple's redesigned Intel 27" iMac will work like this (semi-serious) :
It will work but fans will kick in as much as they do now on 2019 model.
Next year, Apple will put AS into it and fans will be so quiet that you will have virtually silent machine.
Same enclosure but completely different experience.
We are used to Intel iMacs not being super silent so for now it won't change much.
Next year on AS we will get used to new norm.
Of course, this is a little pumped up argument but I hope you get my point.
Intel redesign was and is in the cards regardless of how everyone says 0% chance