@evan It largely depends on how popular the project is vs how steep the learning curve is to contribute.
If the learning curve is flat and the project popular enough, it will quickly no longer be a one-developer project.
If the learning curve is steep and the project popular, the time investment needed for the one developer will be significantly larger if they want to keep their users happy. Then again, they may have just build it for themselves and not care about other users 🤷♀️