How about the equivalent of billboard rental space for being shown in search and related listings? Apple built an app store, it built a reputation for its app

How about the equivalent of billboard rental space for being shown in search and related listings? Apple built an app store, it built a reputation for its app store, and now its featuring your app. And then there is engineering costs for the toolkits, compilers, libraries that are being used to create the binaries they publish. And not a stagnant toolkit, but the expectation that the toolkits evolve. So Engineering as a Service rent fees.