The retail analogy doesn't quite fit. Apple isn't just the shoe retailer[0] they're also the company which supplied Nike with all of the sewing machines and stitching yarn that was used to assemble shoes made with Nike leather and rubber. Nike signed an agreement with Apple which says that in return for an endless supply of sewing machines and yarn, Nike must split the final revenue with Apple.
[0] And even retailer isn't quite right. What the App Store does is less akin to the wholesale-retail model and more like the agency sales model.
[0] And even retailer isn't quite right. What the App Store does is less akin to the wholesale-retail model and more like the agency sales model.