Like radio, podcasting does not have a physical product corresponding to a higher per unit value, as is the case with music (e.g., CDs, vinyl) or film (e.g., DVDs or cinema tickets), because podcasts were born open source on the internet.
This is important because, a key driver of digital subscription adoption in music, TV, film, and games was the fact that they offered a cost saving for consumers accustomed to paying comparably higher prices for the individual physical products. Podcasts, as well as radio, which has always been predominantly ad-supported, lack this in their consumer offering, making it much harder for subscriptions to gain traction. (MIDIA)