It is the distribution of iOS versions among laptops and desktops that violates the tree you put forward. You had two groups that are connected by a node. If a laptop and a desktop share a feature, then that feature is found at the node where those two groups meet. Therefore, if a laptop and a desktop share a feature then other laptops should have that same feature. That’s not what we see. iOS versions don’t follow the pattern of the groups you put forward.
Look at this tree. Notice how all the branches up the tree share the features listed where the branches meet.
That’s a nested hierarchy. If, as you claim, Mac’s form a nested hierarchy then you need to organize them into a tree and list the shared derived characteristics of those branches like you see in the tree above.