As someone who has been creating FOSS for years, having the source code to an application doesn’t make much difference if there is no support or clear path for contributors. It’s no more secure or convenient than a closed source application and I’d argue you’re likely to get fastest returns when issues are reported on the closed source side.

That being said individual components which make up an application have much more value in source code being available if what they do is useful, which is why we go that route.

When other pieces of a program are tied to proprietary backends, paid cloud services like AWS or Azure or run services tied to particular domains, open sourcing it becomes pretty difficult if not impossible without spinning up tons of infrastructure, defeating the point.