[dredmorbius]

This isn't HW integration at the CPU level, but the whole damned device chipset. Apple know what network, WiFi, video, audio, network, camera, USB, FireWire, or whatever else device(s) are going to be on the system. They can buy out entire production runs of hardware if need be. And if there are changes to spec, they can stay on top of that as well.

Linux ... takes what you throw at it. It does this pretty damned well most of the time, but I've lived and seen the challenges.

Broadcom chipsets. Nvidia. Dell's so-called RAID controllers (PERC). WiFi.

Audio, trackpad (at least for single-touch), networking, and WiFi not so much any more, though bootloaders and telco kit remain issues.