Can you explain the Microsoft bit? There's an ocean of difference between Microsoft and Apple. You can pretty much pick any MS API from the past 20 years and it'll still work on Windows 10.
You see the impact on a few things like Office and SCCM today. As the legacy windows platforms fade, it will become a thing in other areas. My guess is you’ll see more “fixed in Azure only” scenarios to drive demand for those products, and act as a sales funnel for complementary services.
It takes less time to test compatibility than it does to compile.