Why? The folks at Senior Planet, a group of active 60+ people found a bunch of reasons:

1. Hearing Aids Are Too Expensive

2. Hearing Aids Are Unattractive  

3. Hearing Aids Don’t Help   

4. Hearing Aids Are Uncomfortable

5. Hearing Aids Batteries Are Hard to Handle

6. Hearing Aids Are Easy to Lose

7. Hearing Aids Make Me Feel/Look Old

In summary, there are two groups of reasons: the appearance and performance of hearing aids themselves and the difficulty of using and keeping track of them.

There is a school of thought that hearing aids should be large and visible, so that persons conversing with the wearer are well aware of his/her hearing difficulty.