Valid post, and given the scale of DnD dragons I'd say that an adventurer is about the size of a cat relative to an adult dragon. IRL, a cat being able to attack you and successfully kill you would be pretty fucked up even if it's theoretically possible.
Incidentally however...
A cat in DnD does have the ability to reliably fight and kill a Commoner.
So what I'm saying is that it should actually be a valid plot to put humans in the position of some shitty media's dragons- once dominant, but through the power of one especially heroic housecat who has exceptionally strong plot armour, we are reduced to a dying race, ancient and forgotten by the new era.
