In D&D, in one of the 3/3.5 books, they explained how resurrection spells work. (I forget which book). They note that in order to be resurrected, the person needs to agree to it. However, the vast vast majority of people find peace in where the soul is sent after they die(even if they are evil), which means they won't accept a resurrection. This means that typically only people who have some sort of important unfinished business typically come back.