Still surprised
That no manufacturer has looked at the hearing aid form factor.
Several days of battery life, even whilst streaming, and comfortable enough to wear all day long.
I can even replace the batteries in mine, and they have space for a few buttons on the back.
The capabilities of the in ear drivers are astonishing (136dB if you get* the high volume ones) with pretty damned good frequency response, and with open silicone bits you don't get isolated from what is going on around you (closed cups do more isolation, full on moulded in ear sections are pretty isolating).
* Don't get these unless you actually need them, else you'll rapidly need them.