I think it becomes increasingly true for projects that are stable and long-lived. Maybe it's even an indicator for such projects! If your project appears to be

I think it becomes increasingly true for projects that are stable and long-lived. Maybe it's even an indicator for such projects! If your project appears to be converging towards "no problems except those entirely outside my control" then it's a sign that your project is stable and possibly nearing feature-completion. Maybe convergence is truly asymptotic and you never fully get there, but the bugs and feature changes get smaller and smaller over time. Not all projects can or should be "stable" in this sense, but it is an interesting indicator.