One reason many songs are no longer heard is they have been over exposed. The songs are good but if repeated too frequently they become stale. Many singers have a limited number of songs and don't make the effort to learn new songs.
I've heard people say things like "not the Fields of Athenry again"
it gets sung about once in 18 months in our club and is treated like an old friend, not that song we've every three weeks for the last year and are bored to death with with