Since you are mostly in FUD mode and showing a clear miss understanding how things work it makes it rather hard to explain it to you.
It would be more like how there are "two version" of iOS out there. One for iPad and phone/iPod. While same in many ways they do have difference in how they handle things. Different gesture support and so on. Minor over all but still differences. Honeycomb added some pretty big changes from the 2.x line so ICS was design to bring it back in line and bring in those changes to the phones.
While unifiy the two they still require difference to take advantage of the large screens better.
So since you clearly are not in FUD mode, let me get this clear hehe. They're going to release Jelly Bean for tablets only, and the next Android smartphone OS is going to be 6.0? Just making sure I understand, since clearly you have an idea what you're talking about hehe..or maybe not.