Well, I agree with this to a point, as well. I do think we don't fully understand chicken illnesses yet, and are looking at them more closely now because people keep them as semi-pets. No one cared about chicken longevity in the past, so no one studied diseases that keep them from living beyond 2 yrs of age.
I think this is true.
However, I will add that I have had birds with neuro symptoms (staggering, sideways gait, not walking), improve when I did nothing at all but provide the usual food and water. If a bird is not eating or drinking, I'll dip the beak in water several times a day to prevent dehydration, but that's about the extent of it. So I personally don't bother with the remedies often discussed here. Some of the birds recover and some don't. Same as when people throw all sorts of remedies at them.
I guess I'm one to throw certain remedies at them... If I have a sick chicken, I always dust for mites/lice, worm, tube feed fluids and baby bird food if they are not drinking/eating and I might even give them antibiotics, but that's it.