As Apple explained …well, explains, in an illuminating 2-minute video, iPhones actually included FM tuners before the iPhone 7. At the time, Apple purchased its wireless/Bluetooth chipset from Broadcom. At the time, Broadcom included a radio tuner. It was Apple’s responsibility to add a simple circuitry upgrade that would have made the tuner functional on iOS.
This they did not do. Per Apple explained, the decision not to include a radio tuner app in earlier iPhones and to remove the radio transmitter entirely in later versions had less to do with engineering than, for lack of a better word, the vibes. Terrestrial radio is an old technology: local, limited range, with varying degrees of quality control. This is not Apple’s offer. Apple is working hard to deliver a fluid, transparent and futuristic user experience with minimal customer intervention and maximum stability across models and borders. Radio couldn’t live up to that, so it had no place on iOS.