Own the whole stack.
Ever has it been thus. Nobody is in Apple's league at owning the stack and so far they have avoided anti-competitive / monopoly issues with a few weird exceptions.
Except the rules of the game have changed. Intel has hit the limit of Moore's law and performance per watt (PPW) as far as their architecture goes. ARM still has headroom they can squeeze and Apple can influence the ARM architecture in ways that Intel will never allow. Plus bringing the CPU...