I've always thought of dragons as an archetype, the universal monster, as they've appeared in virtually every culture throughout history (including those predating the Bible). I see them as symbols of chaos, of primordial forces, with Eastern dragons representing mostly benevolent, creative tendencies (order from chaos), and Western dragons representing malevolence and destruction (this no doubt largely influenced by Christian mythology).
While we tend to view dragons largely as serpentine-ish, early renditions were more chimeric, suggesting the image has been tweaked and refined over time (eg, google Tiamat), again with Christian influences and associations with the Devil being dominant shapers.
I doubt any ancient findings of dinosaur bones had much influence. First off, they'd have to be recognized as bones belonging to long-extinct animals, and, back then, anything could be misinterpreted, according to the zeitgeist of a time and place (eg, it used to be thought elephant skulls were those of cyclopses cuz the large nasal cavity looked like a socket for a single, giant eye).
Dragons touch something deep in all of us, perhaps even giving form to the basic instincts and functions of our own "reptilian brain."