$1 hearing aid could treat millions with hearing loss
Hearing aids (nor cochlear implants, for that matter) do not "restore hearing", except for light hearing loss. They are only like crutches (not even wheelchair). For example, to follow conversations or phone/skype with multiple people is very exhausting even with fancy device, because in most cases the "bandwidth" to the brain just isn't available.That said, the hearing aids vendor lock-in is really atrocious and can use a disruption. They don't like users configuring the aids themselves, you are expected to make appointments with audiologist - in fact several of them because every hearing loss is different and it's hard to exactly measure, so usually the aids won't fit on first or second try. The algorithms are strictly proprietary - when there's 40dB difference between responses to different frequencies such as I have, usual equalizer won't do. To enable bluetooth the rule is to buy expensive add-on streamer.