Bluetooth.
There is probably a great fear among audiologists that people could be fitted for an ear-piece and then completely tune in the generic component with their smart phones.
On a slightly different topic...live-music pro-audio, the sound-man used to need miles of cable, racks of gear, and a giant remote soundboard, and an onstage monitor board, and some monkeys to help him set it all up. Now, most of that has largely been eliminated.
He needs an onstage “box” to which he connects all the mic and signal inputs, as well as all the outputs to the amplifiers. Then he can walk around the crowd area using his “tablet” with a free software app that can control the whole show. The screen has several views of mixing boards, EQs, cross-overs, monitor boards...everything needed...all virtually wireless.
There could be a “smartphone app” that allows the “patient” to dial-in their own tiny high-tech hearing aid. Since it’s their own hearing, and no one else can hear exactly what they do, once trained they can probably do a better job than the audiologist.
(It has probably already happened)
Hackable hearing devices...
Need to have that done, and open source Linux based programming software...
If someone makes a generic interface and hearing device, then that takes the wind out of the big name mfg $ales/$ails.
I’m all for it; I am severely hearing impaired & sick & tired of having to shell out big bucks in order to hear at a level where someone would -need- hearing aids (best amplification I get with them is -45dB).