Dragons were probably something like Loch Ness & Sasquatch; something that someone may have saw something but it became more exaggerated as they retold the tale. Something like an oversized lizard seen in the dark could've been the bases for a dragon. No explanarion on the fire-breathing part other than, one person lied and others ran with it.
Magic is now explained by pure coincidence of timing and medical anomalies.
nah terra-dacktals were flying dinosaurs...im sure cavemen or whoever came after saw them and their counterparts, which were dragons
and i swear some type of magic or wizarddry has to exist...people arent that creative...it probably existed but the history and those people were merked by Europeans....im pretty sure we will see a mutant similar to x men in our lifetime too