Do you ever wonder?

What about Wynton Marsalis, the revisionist fraud who made a career off of the supposition that innovation was dead and the 'art of jazz' should be about copying the past? He is not a traditionalist. A traditionalist works in a tradition which is based on INVENTION. He invents nothing. He merely gives echoes of bygone sounds.

Example of loads of talent and artistry (it takes both) - watch this

You're puzzled about why the Manhattan Transfer had a successful run? Look, it's not my type of music either, but I can recognize the obvious talent and hard work that went into their recordings (and reputedly performances). I took a jazz arranging class once. The teacher started off the first class by playing an Manh Transfer track explaining all the things they were doing well.

I also wonder why you'd even think to include Norah Jones on the list.

If I had to make a list, it would be replete with alt/hard rock incompetents like Wilco & Poison.

There's a difference between not liking particular artists or certain types of music vs. what I think the original point of this thread which is namely; artists who have achieved success even though they SUCK!;) While I don't care much for Wynton Marsalis I don't think it can be denied that he's a skilled & well-trained musician. The same can be said for Manhatten Transfer. Where as someone like Kid Rock, not so much.

The Steve Miller Band-Take the money and run, how ironic.
Sade-The Kenny G of vocals.
Garth Brooks-A 100+ million Americans are not smarter then a 5th grader.
Nirvana-All that negativity can be fatal.
Eminem-The James Dean of hip-hop.
Nickleback-The real Spinal Tap.