You definitely have a point. We need to distinguish between in-house developed IT-systems, and software sold as a product. They are quite different. For the for

You definitely have a point. We need to distinguish between in-house developed IT-systems, and software sold as a product. They are quite different. For the former, whether a file is a source file or a configuration file often does not really matter. Like you say, they are managed in version control, some build magic happens and they are deployed. Differences between environments, automated tests etc matter, but with that in mind, there is absolutely room for simplification in many cases. For the latter, it is more clear. The developer develops the code, the user changes the configuration