Memory interface and core interconnects are another differentiator, just look at how much they vary on Cortex-A9 SoCs for instance (1x32 bit to 4x32bit, to say

Memory interface and core interconnects are another differentiator, just look at how much they vary on Cortex-A9 SoCs for instance (1x32 bit to 4x32bit, to say nothing of the frequency or memory type)