In many places people with access to latrines still defecate in the open because the practice is habitual, social, or culturally preferred, so simply building toilets does not stop the disease transmission. Changing sanitation outcomes requires shifting shame, status and habit, not just supplying hardware.
Instead of subsidizing toilets, facilitators walk villagers to their own open-defecation sites and calculate how much feces they collectively ingest via flies and contaminated food, triggering collective disgust and shame. The revulsion, not external funding, drives the community to build and use latrines on its own.
George documents Japan's Washlet toilets, which wash, dry and deodorize with heated seats and built-in bidets, selling to the majority of households, while Americans and Britons resist such devices largely out of cultural squeamishness about discussing the body. The same bodily function produces lavish engineering in one culture and embarrassed silence in another.