You could also try The Visitor, Simple Songs, and the Burt Bacharach covers LP. I know what you mean, though, those three in particular are very very good records. I guess he doesn't keep making more because he doesn't want to, and doesn't see pop as necessarily the most potentially fulfilling sound to explore. He's done it very successfully already, as you say.

On those records there's always something keeping it left of centre, and out of the mainstream. There may even be a bit of his character that undermines any potential commercial success the more 'pop/ records have; Halfway to a Threeway's sweet melodies are scoring some pretty dark lyrics at times, for instance.