Also, there are those who argue that starting new projects in C++ in 2023 is almost always wrong. How about checking out the new C++ library? Do you think your preferred language X would be better than C++ in this situation?
Metal started with a programming model that looks a lot like what a hypothetical "D3D11 next" could have looked like (basically D3D11 minus the warts, and plus PSOs, command queues and render passes, but keeping the traditional and straightforward slot-based resource binding model).
Later versions then gradually added optional lower-level, more explicit features which allow more control over resource management and accessing specific GPU features with less API overhead, but may also be less convenient to use (and it's not actually just "Apple GPUs", Metal supports Apple devices with Intel, AMD and NVIDIA(?) GPUs just fine - since there were Mac laptops which shipped with those GPUs).
Apple also maintains higher level libraries like MetalKit and SceneKit.
Because of this 'layered approach', a Metal application can just start with the higher level API features to get something running quickly, and then gradually switch to more recent and more explicit Metal features only when needed or desired.
One could also simply say that the Metal team applied common sense, "taste" and a balanced approach to their API design, instead of just mechanically collecting hardware feature requirements from all GPU vendors and trying to cram those into a common low-level API at all cost.