[ohelabs]

Well for a multitude of reasons....

First it’s on the 2.4 GHz band...which is quite busy as a significant number of devices, and protocols use that band including WiFi, Microwave ovens, baby monitors, and etc. The Bluetooth spec as done a lot to mitigate this in the spec but the issue persists.

Second there is an security element that was kinda added on later but was also built in and was optional.... this causes an untold amount of issues (aka vulnerabilities) and is probably what your experiencing with the paring issues.

Lastly the protocol stack implemented almost everything from audio to serial to TCP/IP...which is probably why it’s so ubiquitous and is implemented weirdly because there is multiple ways to do it...see the number of Bluetooth codecs.