The town of Phoenix, Arizona Territory was very different then it is today.
Phoenix had a population of slightly over 11,000 people that lived within 3 square miles. Phoenix was protected by a police force of 3 officers. Officers were carried to crime scenes by Old Nelly, a horse that pulled their patrol wagon.
In 1903, each officer serviced nearly 10 times the people than is done today.
One possible reason is most citizens generally took care of themselves and looked out for their neighbors. This could easily be called neighborhood watch.
If more 2003 citizens followed the 1903 example and became involved in crime prevention we might improve our officer per capita ratio?…☺