I just don't want to carry two sets of headphones around with me. Currently, I keep my single pair in my back pocket, so I have them with me everywhere and I can use them with everything.

To be sure, the world would not end if I had to carry around two sets of headphones instead of one. But then, I don't need a faster phone either! New phones today are only adding marginal improvements, and the absence of a headphone jack is a bigger inconvenience by comparison.

Re: Bluetooth, the problem is that switching devices is still finicky. If you only use Apple products the Airpods do a good job at switching devices, but I sometimes use PCs. Also, I lose headphones frequently, and Bluetooth headphones are still expensive.