Apple has a predefined and very limited line of hardware, so it's obvious that Mac OS is well integrated with Apple devices.
... Which is not the only valid approach, of course, but it is compelling to many.
... And the counterargument is that having homogeneous dev and deploy environments has great value. And I agree, but I deploy on FreeBSD, Solaris, and Linux; self-hosted, AWS, and colocated. So I have lots of RAM, virtual machines, staging environments, and a strong preference for low levels of dogma.