There’s this idea in evolutionary biology called the Red Queen Hypothesis. Taking its name from Lewis Carroll’s Through The Looking-Glass, and specifically from the Red Queen’s race in which “it takes all the running you can do, to keep in the same place”, the hypothesis suggests that evolution is driven by species endlessly adapting to each other, so that they don’t go extinct. The prey adapts so that they can avoid predators better, which forces the predator to adapt so they can keep catching and eating their prey, which forces the prey to adapt again, onward and onward.
A pitcher and a batter aren’t quite different species, but the hypothesis might as well apply to them.