I'm not an audio professional and I think there's far more like me that you can't ignore.
USB-C is a nice connector, and for digital headsets it is pretty nice, but it has some disadvantages (and advantages!) compared to standard headphone jack:
1. Portable devices tend to only have 1, so no listening to music while charging. Common in car scenarios, not all cars have BT audio, and BT audio implementations in cars can vary in quality by large factors.
2. Sound degradation over BT is a problem. Recompressing an already compressed file (e.g. MP3) is going to result in a loss of quality. Since a lot of music is streamed at a bitrate that is "just above noticeable loss", further compression will result in a sound quality decrease.
3. It moves the DAC to outside the phone. This is mostly a good thing, assuming the dongle uses a good DAC, and eventually we'll see third party high quality USB-C DACs (as are already present on desktops for traditional USB)
4. Pure USB-C headphones require more engineering, and they require a type of engineering that headphone companies are not traditionally familiar with. Headphone companies are experts in making high quality analog sound systems, shoehorning the need for digital expertise is needless. (Though more and more headphone companies already have a digital team, it does raise the bar for new entrants.)
5. The AUX jack is pretty damn good. Replacing it with a digital jack isn't really needed. Even with a huge industry push, it'll be many many years before USB-C is everywhere, and if you count the professional markets, it will likely be decades, if ever. (This isn't helped by Apple pushing a competing standard!) Digital means software, which means things can and will go wrong. With an analog plug the quality of the signal is the quality of the physical connection and the wiring going between them, and as a species we have almost over a century of knowledge about analog signals. With digital, ideally quality never degrades, but with firmware/software bugs it can degrade, and to get optimal quality it'll require every device in a chain not have any bugs related to sound quality.
AUX is the only standard used by both consumers and professionals, and losing that would be very annoying.
Because BT isn't an improvement. It's a worse experience in almost every way.
Physical improvements have been necessary for USB to increase bandwidth. 3.5mm is a connector for carrying two (sometimes 3) analog signals, and backwards-incompatible changes aren't necessary until we develop a third ear.
Usb-C to 3.5mm jack, where it isn't a dongle, but rather built into the cable itself.
Your storage device has to handshake with the playback device. Maybe HDCP over USB?
There’s many people exactly like that.
Afterwards you can get all parts replaced for basically nothing, though, or buy the replacement parts and do it yourself (I just replaced the leather pads and cabling on mine)
I'll be sticking with my pixel xl