A shelf space analogy doesn't make sense. With a real shelf, there is scarcity. Only so many shelves can fit in the store, and only so many products on a shelf.
The marginal cost of a virtual good is zero. Apple's ability to support apps is effectively infinite.
The marginal cost of a virtual good is zero. Apple's ability to support apps is effectively infinite.
There are over 1M apps in the App Store.
This is not about "shelf space".