Do you mean a 12-band equalizer? That would allow a tailor-made frequency response.
From what I understand the greatest need for a hearing aid is in senior citizens who lose hearing in the upper frequencies.
It would take an unusual pattern of hearing loss to need 12 bands of adjustment.
I found hearing aids for my mother on Ebay. Tiny, in the ear (not on the ear or around the ear). $350 a pair. They're not 12-band. One little knob adjusts volume. Another smaller knob adjusts frequency response. I can use them when I'm my mother's age because she didn't want to use them (no matter how much she needs them). I tried them and I noticed an outstanding boost in both volume and high frequencies.
I didn't care to go to a doctor. I knew he would charge a couple thousand dollars. The device itself is a minor part of the cost. The majority of the cost is for expected follow-up visits, testing, adjustments, etc. The keyword is 'expected' because the doctor wants to charge a patient enough to cover all his anticpated expenses. Maybe some goes into making molds of a person's ear canal, I don't know how often they want to make it that much effort.
I don't know how much money would go into the cost of the device in case of a 12 band hearing aid. I suspect that making them doesn't cost nearly half of the $1000 you quoted.
However the makers realize a customer expects to pay a lot of money. It has to do with the hope-for improvement in quality of life, as much as cost of the device itself.