Dragons may have been used as a deterrent to keep children inside the house at night.
Human history is full of violence and the like.
Rape, kidnappings, murder, and countless atrocities are comitted these days....... Imagine living during a time when there were no police readily
available and thieves and brigands could be no more than a stones throw away from your home waiting to rape, torture and than kill your family.
It would seem to me that a 40', scaled, lizard that breathes fire and hunted at night would have been a damn good reason to stay in the house if you
believed it was real.
A few theories to explain no remains, perhaps if dragons did exist they ate their dead? Or perhaps the mechanism with which they breathed fire would
cause them to spontaneously combust upon death? Or like the movie: Reign of Fire, dragons die out eventually from lack of food and a single male and a
rookerie full of eggs is all that is left of their race, waiting for food levels to replenish themselves. Like it or not people, humans are a
renewable resource!