Granted there are no easy answers, and you lay out very succinctly the many factors involved in the decision to suspend or not.

I have been in similar situations, where an unproductive search has continued and you are faced with the decision as to terminate. Two instances in my experience stand out. In both situations the intensive, ground pounding phase lasted for two weeks (in one case slightly more), followed by several efforts focused on particular localities and environments. In both cases there were very real concerns as to whether the individual sought was actually executing a planned disappearance - a question that has not been answered to this day, since both cases are still unresolved.

You mention the availability of resources, especially searchers, and this is where volunteer SAR organizations can really contribute, since an organization of reasonable size and competence can contribute bods for prolonged periods.

I don't know about the stated policy of other organizations, but the saving of lives is paramount within the National Park Service. Costs are typically minimized by using volunteers to augment a core cadre of trained staff. In or out of the NPS, I have never heard of a search being suspended because of costs.

I still feel that suspension of a search effort after seven days is cutting it off too soon. In this case, the victim was clearly still alive. It is a shame that her signalling efforts were not better or that searchers missed what might have been a significant clue.

By the way, if anyone encounters either Donald Lee Curtis or Paul Fugate, please tell them that we left a light on for them in southern Arizona.....