There are a huge number of reasons why people with hearing loss choose not to get hearing aids. I do not personally have any hearing loss, but my best friend and former housemate of three years (who is now an audiologist) was profoundly deaf in her left ear and severely deaf in her right ear, and we spoke about hearing a lot which is why I have some knowledge of this area.
Firstly, all hearing aids do is amplify the sounds which enter your ear canal – all a hearing aid is made of is a microphone, amplifier and a speaker. For some people, increased amplification helps them immensely. Without wanting to get complicated, for some people, the nature of their hearing loss means the noise signal they hear is very degraded, and simply amplifying it will not help the clarify of the message (in the same way that raising your voice or shouting at a deaf person may not help them understand you any better). If someone has a hearing loss of this nature, a hearing aid may be unhelpful.
Secondly, there are huge variations in the quality of hearing aids available. Here in the UK, our NHS provides good-quality modern digital hearing aids for people for free (unfortunately you do have to wait a while!), but I don’t know about the situation in other countries. Certainly, my friend never wore her older hearing aids because they were absolutely useless – they indiscriminately amplified all sounds, not just speech, so the rustling of clothing, food packaging etc became as loud as someone’s voice – hardly pleasant or helpful. These hearing aids are at the cheaper end of the market, and if this what you can afford, I can understand why someone would choose not to get them. If they can’t afford a really good hearing aid that will really help them rather than cause them irritation and frustration, I can understand why they might not bother at all.
Thirdly, it is sometimes very difficult for a hearing person to appreciate what it is like living as a deaf or hearing impaired person. My profoundly deaf friend and I have had conversations where she has said if she could choose to have perfect hearing or stay as she is, she would actually prefer to keep her hearing loss. Her loss is congenital, rather than something that has developed over time, but I can completely understand her reasoning – she likes her quiet world, and prefers not to be bothered by sounds that can annoy a lot of people (doors banging, dogs barking, traffic, etc.). Her new hearing aid helps her at lot, but she chooses to wear it only at specific times, when she feels like it.
Fourthly, as others have touched upon, there is a degree of stigma, discomfort, anxiety, embarrassment, shame, and so on, that can sometimes be attached to seeking help for hearing loss, and wearing hearing aids. I’m sure you understand that this is a really big issue for some folks.
Fifthly, for the situation you describe where you are trying to communicate on the telephone, sometimes hearing aids aren’t effective in this situation. As you commented, many deaf people rely on lipreading for speech comprehension, and for some people, depending on the nature of their hearing impairment, telephone conversations will always be a challenge, whether they have amplified what’s coming down the receiver with a hearing aid or not.
I totally agree with you that it is frustrating when you see someone that you perceive to be struggling with communication, when it seems like a hearing aid could really help them. If it was someone I was really close to in this situation, then I might sit them down and see if they wanted to talk about the situation. But it’s such a deeply personal thing (as a lot of health problems are), that if it’s someone you aren’t very close to, I guess you just have to be patient with them. I totally understand that the communication can be difficult and frustrating when you talk to someone with hearing loss, but I think what you have to remember is that is what every conversation is like for that person, every day. It’s such a personal thing that I think the only thing you can do is respect the person’s own decisions they make about how to manage their condition, and offer advice only if it is requested or seems really appropriate (i.e., someone you are very close to).