The idea of 'source only' is not new at all. Back in the late 90s when Delphi was popular, many developers created and sold components to other developers (e.g. UI widgets). These components came with full source code of the components but they were not open source.
Fast forward to today, what are examples of 'source only' products doing well? Two examples: 'Kirby CMS' and 'Craft CMS' (Content Management Systems). Both are popular and profitable. Their source code is even published publicly on GitHub. The product creators trust customers will pay for the product (presumably some do not, but don't matter to profitability). Other developers are happy to contribute to the eco-system of plugins. So, yes, you can also build a community of enthusiastic followers for a product that isn't open source.
The label 'source only' is considered a dirty word among some open source advocates. But if you are building a B2B (Business-to-Business) software product, 'source only' is a viable option to succesfully make a living from your product - one that isn't completely closed source. (The GPL family of licences let you pay for the distribution of the source code.)
What are you thoughts on the 'source only' option for software products? Is it something you would consider? Why is this option sometimes maligned?
A major theme in the ‘open source community’ is people badmouthing commercial software (Stallman would say you are a bad person if you use Microsoft Windows, an iPhone, or even drive a car with a proprietary engine control unit.) or other kinds of ‘open source’ software that other people think is harmful.
It is best to let those people torture each other rather than ask why they do it or (worse) join in.