‘With In Rainbows I found the download software so awkward that I fired up LimeWire to do the download *after I had already given the band $15*.’

So…

Why not separate the sale of copies from the sale of the art?

If the copy costs nothing to make or distribute, it’ll end up being priced at zero (in a free market).

Whereas the art, being expensive in labour, time, and skill, you can pay a commensurate amount for.

Sounds like a fair deal to me: “Audience make your own copies. I’ll only sell you what you can’t make yourself: my art.”