This. Nothing is more difficult than understanding someone’s else code and architecture, and even if you manage that, you’re now stucked with the choices somebody else made and nobody wants that (we want to make our terrible choices!).
More than a final app, the best thing to publish as FOSS is libraries extracted from it to help other developers build there own products faster. That’s something other may want to maintain when we abandon it. And on top of that, it still help to publish your app using this lib to serve as practical example about how to use your it, of course.