Yes, I know owls have feathery "ear tufts", but these are less suited for hearing and more for display.
And I find it hard to believe that animals like dinosaurs or other cursorial archosaurs would not rely on sound as much as a mammal would. It's just too useful of a sense.
One potential clue is the fact that most non-mammal tetrapods appear to use electrical tuning to discern different sounds, whereas mammals use the hair cells of their longer cochlea to mechanically discriminate sound. I feel like this is related but not completely connected to why a fleshy outer ear structure that can collect and focus in on the direction of a sound.
Why did the pinnae evolve in mammals and why are they the only ones with such a structure?