I love my AirPods. But the instant I have to start digging through screens to do a pairing dance with some third-party speakers, car stereo, etc, I pine for the simpler times when you could just plug in the AUX, and I mourn for what has been lost.
You can literally hear how much worse the bluetooth audio sounds in my wife's care compared to mine. She uses the aux port because it's so bad.
In particular there is a wide variety of required gain/impedance as well as multiple different proprietary options as people attempted to adopt it to add microphones, controls/signals, and/or video. This is why Android, Apple, Microsoft and Playstation all have incompatible accessories.
The number of contacts can vary between 2 and 5. The length of the primary contact is not consistent, thus the mechanism to retain the plug often does not engage. Likewise, there is no specification on overall plug size to guarantee a jack will fit into the device case.
Thats excluding other extensions such as toslink. It is also worth noting that making the wrong connection, e.g. attaching an AV output to an audio input, can physically damage equipment.
Generally what people see is that the headset they got for whatever device works and assume there is broad compatibility - but to work best the jack on the headset is being designed for and tested against a particular subset of supported phones/controllers/music players. And broader support is typically not possible without separate connectors (e.g. a headset cord sold for apple, for xbox, for playstation, for android).
Anyway, I'm happy they are including a genuine, pretend-spec'ed 3.5mm audio output jack in their newest laptops.