While this is commonly said about PC and Windows, Microsoft actually publishes pretty clear standards that Linux even reuses, because they do not control the hw vendors.
Apple has both hardware and software in one house. On one side, this means that they can escape the trap that cripples performance of competing mobile SoCs (as they don't have to deal with price competition for SoC itself), but it also means that they don't have to follow any form of standard with hw/sw interface.
Thus you have the reason for majority of hackintosh tricks, special cases in Linux for running on Macs, and Bootcamp. Because if it's quicker to "quirk it" in Mac OS X than fix it properly, it will be quirked. This goes all the way to simple things like putting HDA configuration data in wrong place in memory (so standard HDA driver is lost trying to init hw on mac, and macos is lost trying to init it on standard-compliant machine), to things like making such a hash out of boot process (in order to implement similar behaviour to old Macs) that in some models if you accidentally used standard boot interfaces you'd brick the laptop.
Similar issues are how ARM is still, effectively, not an usable open platform, especially open source boards, because making an SBSA-compliant machine that has properly done ACPI and UEFI is much harder than slapping minimal effort on top of uboot where the only reason you can run a kernel not specifically built for the device is that people complained about lack of upstream kernel, and kernel devs refused to add more machine defs. It's still a giant hack in the end.