Interesting timing. As I was typing the above, PBS was airing a tribute to George Gershwin. Right now they're showing an old home movie where G, Gershwin talks aobu the history of his song "The Man I Love." It was included in at least two musicals,with no accolades, before he finally got it recorded by Helen Morgan, after which it became an American standard, recorded by many artists.
I'm reminded of how MGM studios tried very long and hard to cut "Over The Rainbow" from "The Wizard Of Oz," and how a number of other songs that ended up being very popular were initially rejected by the studios, the radio stations, audiences in general, and even the composers themselves.