It's just closed source drivers stored in private Linux forks (or Apple's code dungeon).

There's nothing inherently special about their optimisations, but hardware is incredibly complex and without documentation, open source drivers cannot be written that are anywhere close to what engineers with hardware docs can build.

Asahi Linux is a great example. It's an unbelievable project but still far from first party Apple drivers.

Once the hardware can actually be used, competition in the OS space will follow.

They have no incentive to offer documentation and competition is bad - so they won't allow that. Regulators must step in here.