There are two types of dragons in the world today. Smaugs are bat-like lizards that can grow up to 30 feet, with a pair of arms and legs. They also sport a pair of large wings that allow them to fly. These dragons inhabit the western world. On the eastern side, a species of dragons called shenrons are dominant. These are serpentine lizards that can fly similar to how snakes move on the ground. Their forms grow upwards of 40 feet, but possess no limbs. Both of these types have the capability to breathe fire. Their bodies and internal organs are protected from their flames, guaranteeing that they are not harmed by their own abilities.
Dragons are hunted and skinned like regular animals, and then turned into items for humans. An industry has developed in which dragon-hide is turned into clothing, from coats to gowns to boots. It has been promoted that these items protect the user from fire, making them flame resistant. However, the individuals that have tested this theory after purchasing them died hideously hilarious deaths. They burned to a crisp, gaining no protection from the dragon-hide covering them.
Why would people not gain the flame-proof protection from dragon-related clothes?