Well, an obvious link between the first two is "J.K.". I don't know about "The Affluent Society" but if you look it up I wouldn't be surprised if there was a "J.K." involved there too.
Yes, that's it. The Harry Potter books are by J.K.Rowling; the lead singer of Jamiroquai is Jay Kay; The Affluent Society was written by J.K.Galbraith.
Money? I'd say..
By the way, In regard Harry Potter as a plagarism of sorts of he greates books of all.."The dark is rising trilogy" Susan Cooper
Cheers