I found this on Quora. It is accurate?
"ARM, when Apple first decided to start using it, had really crappy memory bandwidth, and no ability to engage in out of order execution of instructions, and a very bad GPU.
Apple bought PA Semi, which had been founded by people from NetScaler. The people they bought were very, very good at chip design. This is the path they followed, in reverse order:
NetScaler was acquired by Citrix
People left to found PA Semi, because they didn’t want to work for Citrix
DEC was acquired by Compaq
People left to fou