Whatever, I find it perfectly acceptable, but I'm not one of those kids with headphones in my ear 24/7.
They last days and days for my usage if I'm using them as a headset. They last all day for my usage as music headphones.
Personally, I have these things called 'speakers' in my car and home. They are connected to these wonderful appliances called 'amplifiers,' and they run off the car's (or home's) electrical system. They reproduce sound far better than any headphones.
Even my big-*** Sennheisers don't compare, so tell me why again would I need more than around 5 hours of music playback on my phone?
(When I fly, there are these wonderful things called 'books,' and nice quiet places called 'lounges,' and a boring thing most would call 'work,' that I'm too busy using or doing to listen to music)