You are largely resistant to the black plauge, though, if you’re of European descent. It killed a bunch of people when it initially evolved, but never really went away. The humans who survied had modest resistance and adopted social habits that were both passed on to their kids. (Nowadays it’s a simple course of antibiotics)

Your larger point stands, though, since part of the end of any pandemic is the overly effective pathogen succumbing to the evolutionary pressure to not kill the host, since the bacteria that infects living animals does terrible when those animals die.