@coltrane1: If it’s Soul music you want, there is one current "act" I can enthusiastically recommend: The War & Treaty. An unlikely name, but this husband & wife duo of Michael and Tanya Trotter are absolutely fantastic!
They came to my attention solely for the fact that their debut album Healing Tide was produced by a favorite of mine---Buddy Miller. I don’t know who put the Trotters and Miller together, but the results have to be heard to be believed. Buddy started out in the Contemporary Christian Music field with his eventual wife and musical partner Julie. When he evolved into the secular market, he ended up as guitarist, harmony singer, and bandleader for Emmylou Harris (a position previously filled by Rodney Crowell).
A "Country" musician (he’s far more than that) producing a Soul duo?! Perhaps because he came out of Gospel music, as did Soul music. The duo have VERY strong voices, and the album’s material is excellent. Emmylou joins the duo on one song, the result being fantastic 3-part harmony (Emmylou is a master at singing harmony), which we all love. Right? ;-)
Healing Tide is the strongest debut album I’ve heard in a long, long time. No studio tricks were used in it’s making, done at Buddy’s home studio in Nashville. I use the term literally: Buddy turned his entire 19th century house into a recording studio. When Julie isn’t feeling well (she’s somewhat sickly), he runs a mic cable up to their bedroom, recording her in bed ;-) .
While not wishing to appear argumentative, I must take issue with your proclamation that "Jazz is the most complex music ever created." All Jazz? As in all genres, there is a range of complexity found in Jazz. But more importantly to me, are we to ignore the Baroque era in Classical music? Now THERE is complex music! J.S. Bach was an absolute genius, no secret there.
As for a 4-chord song, I’ve heard a fair amount of Jazz that is composed of less than that, sometimes only one chord, as heard in the music of the "Modal" movement. And then there is the issue of the relationship between complexity and quality. Is quality determined solely by complexity? Using that yardstick, ALL Blues sucks.
For an example of a song that superficially sound simple and non-complex, listen to "God Only Knows", written by Brian Wilson. If you try and play the chords of the song on piano, you are in for a surprise. The chord progression and use of modulation, bass inversion, counterpoint, and other musical devices is surprisingly sophisticated. His peers (including Paul McCartney, Elton John, and Leon Russell consider him a genius. But he’s no J.S. Bach ;-) . Another example is "What Becomes Of The Brokenhearted", my absolute favorite "Soul" song.