I can’t tell what are your assumptions about software here. Are you thinking that software is written once and never enhanced? That there are no questions from users regarding the use of the software? If this is the case then software is a product and could be sold once. However, once you accept the inevitability of the software being enhanced, changed, and fixed as well as providing a means to support Q&A for the software then you either have to charge for these or discontinue the product. 20+ years of software development within the industry has shown this to be the case.
I’ll also add, because you might go down this road, that people HATE paying for software support. Corporations will do it, but individuals will NOT pay for the time value it takes to answer a question they ask. In fact, they get openly hostile when you tell them they have to pay to have a question answered. As you’re no doubt aware, the subscription model partly arose as a way to deal with how to deal with software support.
