I believe that Singer/Songwriter is a record company term. The music business (record companies) found out some time ago that they could make more money opening ancillary publishing houses and receiving royalties without having to pay other publishers who owned populzr songs. If the artist did in-house songs and put the material into their firm, recording companies could make enough money to keep them afloat. This spawned the Singer/Songwriter.
I believe that there is not really a Singer/Songwriter but a good song. The artist may or may not sing them. I don't care who wrote them, personally. If a song is good, it will live on (have legs) regardless of who wrote it. Todays writers are not much different than writers of yesterday in that there are many forgettable songs from the past as well as there are today. The image of the Singer/Songwriter is an outgrowth of the music business and it started in the sixties and seventies with the likes of Joni Mitchell, Dylan, Carly Simon, James Taylor and others. Some of their work will endure. My favorite songwriters could be called Singer/Songwriters by the music industry because they sang the songs they wrote professionally. Tom Lehrer, Woody Guthrie, Irving Berlin, Tom Paxton, Jean Ritchie, Jimmy Driftwood, Bob Miller, and all before Dylan was on the scene.
There is nothing wrong with Singer/Songwriters as an image or genre. But within it includes the writign of songs that will endure and those that won't.
Frank Hamilton