Vatican II shattered the view that the Church was an immovable, truth-holding institution. It led to a global decline in monastic orders, and now we finally have evidence on its impacts on the masses. It greatly reduced religious service attendance: -4pp per decade, 1965-2015!

The old adage that 'the more liberal the church, the emptier the pews' seems to be true not just in the case of small Protestant denominations. It's also true in the case of Catholicism, the world's oldest continuously institutionalized religion.