Simple. There are multiple codecs in Bluetooth headphones, the most used one is proprietary aptX from Qualcomm. Apple has no problems licensing it for Macbooks

Simple. There are multiple codecs in Bluetooth headphones, the most used one is proprietary aptX from Qualcomm. Apple has no problems licensing it for Macbooks and iMacs, but for iPhones they chose to reject Qualcomm, do their thing, and use AAC codec, which is supported only by small fraction of wireless headphones. https://darko.audio/2017/12/how-to-enable-aptx-hd-bluetooth-audio-on-your-iphone-ipad/ https://darko.audio/2017/12/how-to-enable-aptx-hd-bluetooth-... So, if your headphones don't support AAC, they will (most likely) fallback to SBC encoding with a subpar sound quality. Don't want a subpar sound quality? Buy Airpods. Or Beats. Or some other overpriced thing that understands AAC. There was some 100 year-old industry standard regarding sound transmission, but apparently it's "obsolete" now, because Apple said so. And bundled headphones don't sound too good. The removal of headphone jack was purely a political decision to spite Qualcomm and screwing over Apple's customers.