What explanation is given for why there are more ghost stories in a long settled village

The narrator notes that, "Local tales and superstitions thrive best in these sheltered, long settled retreats; but are trampled under foot, by the shifting throng that forms the population of most of our country places." Places where populations are constantly in flux tend not to develop the strong senses of myth that long established places have. A settled population with long standing families keep myths and legends alive and in the area. More transient populations water these myths down and slowly they disappear.