Frankie Armstrong could sing a half-hour ballad, and I'd be spellbound. Same with Judy Cook, or Art Thieme, or a number of others who know that to sing a long song properly, you have to be a storyteller. They lasso you in, and hold you in thrall for as long as they like - and then you beg for more.
If a long song is boring, it's the singer's fault. Well, it could be the song's fault, but then the singer should not have chosen that song.
-Joe-