Quakers are a free-thinking, decentralized sect of Christianity, founded during the enlightenment, with a long history in the US. Quaker high schoolers have the highest SAT scores after Jews and Unitarian Universalists (which isn't really a religion), indicating they are intelligent:
But Quakers as far as I can tell are a dying sect. They are decentralized, but none of the diverse congregations of Quakerism seem to have developed into something with high birthrates and high retention, like Mennonites, Orthodox Jews, or Muslims.
What is the reason for this? Why have none of the intelligent Quakers used their intelligence to develop a sect of Quakerism that works in today's world?