True. Even the interior of an airplane cabin is lined with plastic polymers all over and this is just one of a few layers protecting you from the atmosphere and oblivion below!
Price is based on what a person values something to be worth it to them. I am in Singapore visiting and I see condos which are priced beyond $2000SGD/sqft that I wouldn't see folks paying, even in San Francisco Bay Area for. Then again, the value and pricing that folks place on these is different than what I would be comfortable or agreeable to. Why do you think folks would never move away from Kansas or Texas, knowing that they have acres of land and a home worth <$50/sqft?
Same with anything else, same with headphones. At the used price, the HD700s are well worth it to me, more so than the HD800s used pricing. I wouldn't pay retail for these though.