Where can I get my superhero powers?
I've got tinnitus and moderate hearing loss in the mid-highs. This means that whilst minding my own business walking on a path, I get all of the following amplified because they are in similar ranges;
Road noise. It's not all deep rumbling.
Bits of car stereos.
People speaking.
Any water on the road.
The wind across me, behind or towards me. The HA tries to allow for it, but it moves, as do I, so it's never coming in one fixed direction in relation to my position.
The leaves in the trees.
The tinnitus.
The sound of the HA itself. Slightly less annoying than the Tinnitus. But not by much.
The sound of my trousers, coat and bag as I walk.
My footsteps on the path. Worse with gravel or shared path textures.
My breathing.
Some birdsong. Which is quite nice.
The HA automatically switching to sounds in different directions and on/off depending upon what's going past, the weather, the predominant frequencies and whatever its programming deems appropriate.
And I'll add in something else that falls directly within the frequency range that the HA is already amplifying to an equal volume as all of those - a bicycle. The wheels, tyres and chain, like those other sounds I've listed, are slap bang in the frequencies that need to be amplified in order to understand human speech, particularly sibilance and voiced, unvoiced or where there's elision in consonants (plosives aren't too bad, but in fairness, they're also very easy to lipread). So they're drowned out by everything. Which means I'm unlikely to hear a bike coming, unlikely to hear a cyclist wittering behind me and the chances of actually being able to place a bell sound from behind as being behind and approaching is minimal.
I'm also walking forwards - walking backwards or repeatedly spinning around to see whether I can catch a cyclist I don't even know is there because of the rest of the noise is somewhat impractical. I do not have eyes in the back of my head, despite what my children and pets grew up believing, nor do I have rear view mirrors or glasses that give me the visual field of a rabbit.
You're approaching from an auditory dead spot and a visual blind spot but seem to think that none of that matters as somebody like me will have 'learned' to see more.
To become, as you so blithely declare in your repetition of the The Disabled Have Superpowers Ablelist trope, 'more observant' like 'most deaf people', is simply not true.