I agree. I think that SS harbored hope that the monster would leave when the money arrived. And he knew that even if the cops drove up his driveway, the family would not be out of danger. DW would probably slit his wife and son's throats if that happened. So he did not try and send any signals. He did the opposite. Sadly enough.
I agree with many points you make 123. Certainly takes balls to invade the home in broad daylight and take four people hostage. The logistics of being successful in doing this without one person being able to send out a 911 call would not be too favorable if this was a one person show. And then to hold them for 19 hours! Very bold. So many things can go wrong in 19 hours. Unexpected guests could show up, PS's classmates could stop by to drop off homework,or the daughters could call and freak out being unable to reach anyone in the family. How would DW have known what to expect? Wouldn't he have noticed bedrooms that were obviously those of teenage girls? When were they going to walk in the door?
I also agree that $40,000 was nothing compared with easy pickings in the house. Jewelry, watches, artwork, high-end electronics, collectibles, etc. would have made this a profitable day's work. Why risk the possibility of getting caught by staying overnight.
And then the fire. Yes, what else could you do to bring the authorities to the house as quickly as possible.
So many actions that are very difficult to explain.