Were herbivores only prey?

No. Many were large, well defended or socially strong enough to make attacks dangerous.

Were predators always superior?

No. Hunting was risky, could fail and always involved the danger of injury.

Such features can be understood as responses to predatory pressure.

No. Large and well-defended herbivores could make an attack extremely dangerous.

No. Above all, it is about ecological roles, adaptation and evolutionary pressure.