"The productive forces were conceived by Marx as including means of production and labour power."
"Relations of production are constituted by the economic ownership of productive forces; under capitalism the most fundamental of these relations is the bourgeoisie's ownership of means of production while the proletariat owns only its labour power."
I thought that Doug's stimulating comment and Catherine's reply were indeed relevant to the role of pop culture, which has been extensively commodified, but is also an arena for struggle.
What people think and dream about is not necessarily a commodity, but the very first external source Marx quotes in Capital Vol 1 is this passage by Nicholas Barbon:
"Desire implies want; it is the appetite of the mind, and as natural as hunger to the body ..... The greatest number (of things) have their value from supplying the wants of the mind."
It seems likely that music and dance have been indispensible to human coperative production since at least the mesolithic cultural revolution of 30 to 40,000 years ago. It is a powerful way of promoting unity, which in turn is of course enormously powerful. It can play this role under different relations of production from primitive communism to advanced monopoly finance capitalism.
It is not surprising that it is a highly contested area.
Chris Burford London