As evolutionary time is measured, we have only just turned up and have hardly had time to catch breath, still marveling at our thumbs, still learning to use the brand-new gift of language. Being so young, we can be excused all sorts of folly and can permit ourselves the hope that someday, as a species, we will begin to grow up.
Evil can be undone, but it cannot 'develop' into good. Time does not heal it. The spell must be unwound, bit by bit, 'with backward mutters of dissevering power' - or else not.