Someone made a bunch of money a few years ago selling singing pickles. Doubt there was a sudden human need for singing pickles. Someone created that demand.

If they made the choice by their own volition (even if it's influenced by the marketing) may be they had some need for entertainment or consumerism fulfilled by it?

To disprove supply/demand means that no matter the price of the pickles the number of pickles sold wouldn't change.

"There is no X in Y" is not a proof that "There is no X".

The MIT Press had a book in the 90s called "Philosophies of Manufacture" that gathered together writings, pamphlets, letters and more that flowed around as the industrial revolution ramped up in the USA. It is filled with the actual industrialists and/or capitalists fretting about how there would not be enough demand for their products, and openly formulating plans to increase demand via new means (which today we would call advertising and marketing). This is not some idea flowing from progressive politics, it originates with the capital class itself.