One good thing about persistent evils is that they are instructive. We can generally rely that human ingenuity will continue to exert itself against the things that irritate us. Years pass, the enemy changes form, reinvents itself. But, given enough time, and a little luck, sometimes we win, and even evils of long standing fall asunder.
It helps, also, if occasionally evil rears its head nice and high, and gives us all a good, close look.