>>16900658Presumably they were inspired by giant reptiles (crocodiles, maybe) that wandered out of their normal habitats and ended up in bits of Europe and Asia where the people didn't expect to see lizards longer than a man is tall.
Earlier European stories had their sizes and abilities much more reasonable. The Asian ones were deified, which is how Asian animism dealt with pretty much everything.
As for modern implications, on one hand there's fantasy literature (Tolkien, et cetera) and the tabletop roleplaying games based off them. On the other hand, there's a sizable community of Furries commissioning adult art of them.
I'm going to assume that if you wanted to be a furfag you'd be on tumblr rather than here.