There are many other countries that have similar poor plumbing infrastructure like India, but no where near the rates of open defecation. I had a friend who took a summer job in Mexico with an NGO that built pit-style toilets, and the villagers used them.

Heck, even within India itself, the vastly different open defecation rates between Hindus and Muslims point to the fact that the main factor is cultural, not just logistical.