Maybe that is a legitimate concern for flight attendants, but I totally reject there being any measurable impact on my hearing from riding in a 737 a few times a year. Particularly when I also do other activities like walking down sidewalks next to traffic, which is typically louder and very often MUCH louder (every time an emergency response vehicle drives by blaring a siren which incidentally incorporates white noise.)

Headphones and earplugs are uncomfortable when worn for several hours in a row, either because they are inside my ears, or because they are bulky. This is a matter of comfort, particularly since I try to pass time on planes by sleeping. A noisier commercial airliner, all else being equal, simply is more comfortable than a quiet one.

(I dare say sleep loss and jet lag have a more measurable impact on my health than whatever hearing loss is induced by a typical commercial airliner.)

>like walking down sidewalks next to traffic

Traffic noise is usually much more intermittent, unless you're walking next to a busy freeway. You just hear cars as they go by, but it's not usually a constant. Ears handle intermittent sounds much better than constant noise, even when the intermittent sounds are much louder. It's a lot like radiation exposure: it's cumulative.

>A noisier commercial airliner, all else being equal, simply is more comfortable than a quiet one.

Honestly, you sound like someone who already has a lot of hearing damage.