Because Google And Apple have come to an agreement. Same with Amazon and Apple as well as Amazon and Google (Youtube is finally on FireStick). Also it's not the size of the business but the value of your product and how much you are willing to give into the deal. Epic wanted to cut Apple completed out from IAP as well as get full OS level access with no Apple approval or supervision over the Epic Store that will be selling other developers apps. What kind of deal was that?