It could be that the stats cover mostly recorded music and radio / online play, whereas jazz has tailored itself to serve live performance. And for playing back

It could be that the stats cover mostly recorded music and radio / online play, whereas jazz has tailored itself to serve live performance. And for playing background music, you don't need to buy more albums than you've got. Jazz players can fit into much smaller venues and lower their volume levels. They can adapt their playing, on the spot, to suit the audience. Classical could lower its brow and increase its popularity in a live setting. From what I've read, the highbrow thing isn't historically justified anyway, and the musicians only tolerate the formality because it's expected.