Interesting that #Apple is effectively trying to upend a decade's worth of design philosophy not just for its platform but for the basically every company in the world.
Flat, has been the story of design.
So here is the biggest question.
Will Apple "make specular highlighting great again?
Flat, has been the story of design. It aligns with a lot of the XR aspects of VisionOS and other experiences you see that build depth to UI in a much more visual sense than simply layers.
What replaces it? Glassmorphism.
Whilst described as a noted 2020's trend, it is a UI design philosophy that I think you broadly attribute to Microsoft kicking off and have stuck with since Windows Vista.