The Why Hearing Aids Cost So Much blog post on the SayWhatClub blog pretty much has nailed the question and issue right there. Then they follow up with The Cost of Hearing Aids–Why It May NOT Be About Supply and Demand.
I've always wondered why the prices of analog hearing aids have stayed sky-high over the years, despite many being made and sold? By now, we should have, for example, an Oticon 380P for less than $150. Have you looked inside? Many of the parts can be easily found off the shelf, thus making the total cost cheap, from most good electronics houses. There may be a few parts that may be hard to get. It helps if you have the skills to deal with the very fine wires, tiny parts, and even smaller solder points.
With the right skills and equipment, the hearing aids can be repaired. One website says you can build them for about $300, but it's possible to do for far less than this. You can make a hearing aid that costs less, has AGC, and has the abilities of other hearing aids.
Why do hearing aids cost so much? (Michigan news station)
Hearing Aid Cost
Bluetooth Headsets & Hearing Aids - also has a discussion list/forum
Hearing Aids - Too Expensive?
The slight drawback is you'll look a bit like a Borg if you don't make the circuits small enough and use too many flashing lights. Then again, we're starting to look like them anyway.
As for the marketing angle, marketers tend to make us want to spend more when we really don't need to do so.
Greed at its best.