4.2. Use Value and Sale Value

A software's use value is its economic value as a tool, a productivity mulitplier.
A software's sale value is its value as a salable commodity.
The vast majority of code (about %95) has no sale value: in-house software, embedded software, customizations of programs for the organization, hardware device-drivers or other hardware-assisting software.
Only a small amount of the code (which includes most of the open-source code out there) can be sold or distributed in some way.
Making your revenue stream dependant on sale value leads to many complications: you seek the most buyers (to maximize revenue) but the least actual users (to minimize support).
Once a market matures and sales slow down, most vendors will have no choice but to cut expenses by orphaning the product.
That's why commercial software does not correspond to the "Factory Model":
1. Most developer time is paid for by sale value.
2. The sale value of software is proportional to its development cost and to its use value.