We are still interacting with dinosaurs, we just call them birds. Seriously, though, I assume you refer to conventional dinosaurs, and those went extinct more t

We are still interacting with dinosaurs, we just call them birds. Seriously, though, I assume you refer to conventional dinosaurs, and those went extinct more than 60 millions years ago, at which point the thing closest to a human being was a small mouse-like mammal. It would be very, very improbable that a branch would survive for millions of years without leaving a single indication of its presence, either footprints, fossils, or eggs. There is also more and more evidence that at least some of these dinosaurs actually had feathers, which mythical dragons very rarely have. To some extent we created a representation of dinosaurs similar to how we saw dragons, rather than the other way around. There are still a lot of things we do not know about how dinosaurs looked. There are much less contrived explanations for dragons.