To get the best audio quality amplifiers have to have a maximum output beyond the level you actually intend to use. This does not however mean you necessarily have to allow the customer to actually push the amplifier to its maximum.
On the other hand the warnings aren't new. They even mention the scare stories from the days of the walkman. I'd contend that users should be well aware of the possible dangers and it is their responsibility to decide how loud they wish to play their music.
An alternative to noise cancelling headphones are those that integrate earplugs.
noise-canceling models, which tend to be pricy and unfashionably bulky
So what would be the point of Apple supplying them? Customers will leave them in the box and buy smaller ones. I've no doubt the gold digger bringing this law suit would have done just that.
Using older-style headphones that cup ears can lessen the odds of damage
I doubt many people will ever used such headphones for mobile listening? I have in-ear and foam over-ear varieties. I haven't used those bulky wrap-around models since the early 80s. They weren't just bulky, they also quickly became uncomfortable.
Also despite their appearance many such headphones are actually open, allowing ambient sound to enter.
the "ear bud" earphones sold with the iPods don't properly disperse the sound.
I wonder what difference it really makes. Heaphones are ultimately are speakers pressed right up against your ears.
It's telling that they can't get the maximum listening duration straight - first it is 28 seconds, then an 1 hour and 15 minutes, both of which are wrong.