That's why it's a metaphor, not a strict skeumorphism.
The core ideas taken from the concept of "paper" are stacking, layering, print-design-style blocks of color, and the idea that things can be shuffled and moved but cannot instantly appear and disappear in/out of thin air. That doesn't mean it's literally trying to be a pile of looseleaf, just that it's mimicking those abstract concepts from the real world in an attempt to make the interface intuitive and less "magical" (in the negative sense).
The core ideas taken from the concept of "paper" are stacking, layering, print-design-style blocks of color, and the idea that things can be shuffled and moved but cannot instantly appear and disappear in/out of thin air. That doesn't mean it's literally trying to be a pile of looseleaf, just that it's mimicking those abstract concepts from the real world in an attempt to make the interface intuitive and less "magical" (in the negative sense).