It may not make sense to repair for many consumers. In a few years we might have better codecs or similar and you'll want to upgrade your crusty headphones anyway.
This sounds like something could be done with a firmware update.
The same's true on the smartphone transmitter side.
I notice every time the cost of a properly sustainable product comes up, the conversation always turns to what a short-sighted bastard everyone else is, and I can only assume the people who make that argument are already making moral choices themselves, which is honestly just heartwarming to see.
Bose QC45 => $279
Fairbuds XL => 249€ ($272 if I convert right now)
It's cheaper than two of the most popular headphones, how is there a "too high sustainability tax" ?!?
(These are the most objective measurements I'm aware of.)
[0]: https://www.rtings.com/headphones/reviews/sony/wh-1000xm5-wi...
[1]: https://www.rtings.com/headphones/reviews/sony/wh-1000xm3-wi...
With more mics it's possible to get more accurate NC, especially for directional sounds.
However more mics won't necessarily mean better call quality, they may not even be used at all for voice.
For example my Jabra NC pair has really good microphone quality for calls, this is done by having a dedicated boom microphone, in this case nothing to do with the multiple NC microphones.
The vast amount of Bluetooth NC headphones sound like their 100$ wired counterpart.