Recently Apple added (and actively encourages) the ability for developers to upload bytecode to the App Store instead of ARM binaries so Apple can more easily dynamically recompile for new architectures and optimisations. Of course bytecode is considerably easier to revert back into readable source-code (especially as Swift/ObjectiveC retain (some) symbol names in compiled output) - so it's not outside the realm of possibility that an unscrupulous Apple team is disassembling cool apps to see how they work then re-implement them for the next release of iOS.