What? No ICS update for some tablets. Why?

We've all been eagerly looking forward to I'Ve updates and I owning an ACER Iconia A501 was pretty much looking forward to the end of April because the update was reported to be scheduled for release in Australia. Now I've heard that this is pretty much on the cards for the A500 except that there is no update for planned for the A501. Never? What? Double take. Blink. I figured I misread the schedule... I reread it and it seems to be true.
I can't understand why. The main difference between the two models is that the A501 allows a sim to be installed.
Is there someone reading this who can give me a credible reason why? Now just to set the record straight...will I be disappointed? Yes . But I'll still love my A501. It's a great tab. It does everything I need it to do. I just love the full USB port and the graphics are more than adequate.
Hmm I think I'll just have to be patient.

I have the same issue. Got my Samsung Galaxy Tab 10.1 like 9 months ago and STILL no ICS update. Thats why I rooted it the first day I got it :-D Been running ICS on it for months now.

Well, my patience has been rewarded. The update came a couple of days ago. Nice to have a fresh update...almost like getting a new tablet. (Location: Australia)