> I don't understand why other ARM CPU makers don't come up with comparable CPUs.
This is like asking why other rocket companies don't just build rockets this year that are reusable like SpaceX's.
Apple's CPUs are so fast because they have the best internal engineering team on earth paired with the best Fab (TSMC 7nm) money can buy. They buy out the entire production run from that Fab.
These CPUs are the most advanced and best designed in the world because they worked so hard to get here years ago.
It's like asking why other runners don't just run as a fast as Usain Bolt.