I suppose they somewhat directly contradict Microsoft's model where they try to keep supporting certain API and ABI compatibilities for over 20 years. As 'easy'

I suppose they somewhat directly contradict Microsoft's model where they try to keep supporting certain API and ABI compatibilities for over 20 years. As 'easy' as that is for the third party developer, it might not be the best way to handle an operating system. New insights are constantly gained, and older systems still have faults; the Microsoft model leaves you with a broken system that cannot be fixed until a major redesign, the Apple model leaves you with broken third party software that can be fixed by the developer but nobody else.