Great story! Here’s what I gathered: The founders are in their 80s and may be completely retired. It’s unclear what their perspective is on open source or whether they have considered selling the app to someone (if that someone even exists) who would ensure the same level of dedication that they provided. The code might be legacy, difficult to maintain without a significant rewrite, so the costs of updating the app could be prohibitively expensive.

Now I am curious about what language it is written in, as well as the architecture and other details.