It is plausible that the original non-avian theropod dinosaurs which gave rise to avian theropod dinosaurs like modern birds were more vision-oriented predators than mammalian predators.

That would have favored eyes built for sharper vision at the expense of higher metabolic demands.

The different evolutionary track may come from the fact that theropods stood upright on two legs, so they could scan farther across the landscape. Also, they were active during the day. Early mammals, by contrast, were mostly nocturnal, so hearing and smell mattered more than sharp vision.

Interestingly, humans have some of the best vision in the animal kingdom and humans are both upright standing and diurnal, i.e. active in the daytime.