Here is a proposition that may seem self-evident to many people: As societies become more modern, religion loses its grip. Superstition inevitably gives way to rationality. A belief in magic is replaced by a belief in science.
Sociologists call it the "secularization thesis." In 1822, Thomas Jefferson suggested an early version of it, predicting that Unitarianism "will, ere long, be the religion of the majority from north to south."