Pop stars who sell lots of high-priced concert tickets on the road are finding that their recordings aren’t selling in stores. “Scenarios abound when it comes to the disparity between chart and box office numbers — figures that rarely tell the whole story. In some cases, like with the old guys, it’s that millions and millions of records have already been sold over decades, and fans feel that they have what they need. But sometimes, as with many of the big jam bands, it’s simply the live work that truly drives the train.”