Intellectual property to get cheaper

This article by Paul Krugman takes up the theme that, as a consequence of digitisation and hence of easier replicability, that intellectual property (including software, books, music, movies) will inevitably become cheaper and that products sold in conjunction with the increasingly free goods will become important. Thus the Grateful Dead encouraged the reproduction of its music but sold lots of Grateful Dead teashirts. Digitised books may be given away free but live readings by authors will be marketed with the books.