Anand Lal Shimpi blew my mind with a report:
The A6 is the first Apple SoC to use its own ARMv7 based processor design. The CPU core(s) aren’t based on a vanilla A9 or A15 design from ARM IP, but instead are something of Apple’s own creation.
I had just assumed Apple licensed the designs as they have in the past. I figured with their interest in silicon designs that they would want more control in the future, but not to this level.
This just shows what sort of cash Apple has in the bank. I can’t imagine anyone other than Samsung possibly going this route, and even Samsung wouldn’t likely do it for just one product of theirs.