Just like with music, people prefer just the right amount of cognitive dissonance - noone likes to be told exactly what they already know, and hardly anyone likes to hear something that's completely the opposite of what they already knew/thought.
In music, just a little bit of (harmonic) dissonance catches the listener's attention, but too much gives you a headache. Funny how that metaphor carries over so well, haven't thought of it before.
So I think of people like Gladwell as pop-fusion artists, like say, Jamie Cullum or Michael Buble. They often get disproportionately rewarded (as compared to "real" jazz artists), but they DO do a lot for a lot of people by introducing them to something they otherwise might not have considered.
In music, just a little bit of (harmonic) dissonance catches the listener's attention, but too much gives you a headache. Funny how that metaphor carries over so well, haven't thought of it before.