The supply and demand curve model is either tautologically true (when applied in retrospect), or essentially entirely useless (if you try to use it to model a future product/price).

The cost of reprodcuing a pile of bits is quite unimportant compared to the cost of producing that pile of bits the first time around. This dynamic is poorly captured by supply/demand, and this is where copyright laws have always come in. While they are being abused with absurd expiry limits, they are a necessary part of any kind of money-based society.

Without copyright, for-profit companies would insist on ever more draconian DRM and software obfuscation technologies to replicate similar systems, while liberally taking any piece of code they can get their hands on - whether open-source or from another company with inadequate copy protections.

This basic problem would remain true even if all software and media companies were worker owned syndicalist co-ops.