If "cult" religions are so good at mind control, why are their attrition rates so high?

Sectarian and new religious movements enjoy only a very modest amount of success in recruiting and retaining members in the U.S. If there is a secret mind control technique at work, it is not a very good one. The only realm in which sects and NRMs are wildly successful is urban legend.

Here's a thought experiment:

Give your best and most liberal estimate of the peak number of Moonies (a/k/a Unification Church members) in the U.S. in the last fifty years.

Most people will guess that it is a number over one hundred thousand; in fact, Unification Church membership peaked in the 1970's at around ten thousand, and that included Unificationists from Korea and Japan who had married U.S. citizens and came here to live.

Since then, membership has fallen off and stabilized somewhat, but attrition rates for new members were always high. In fact, this is one characteristic shared by a number of high profile but otherwise dissimiliar NRMs.

While working on my theology degree I had the opportunity to study at the Unification Theological Seminary in Barrytown, NY and interview both professors and participants of the Unification Church¹. Ten thousand members in the U.S. would strike me as very unlikely.

In 1982 alone the Unification Church married 4,150 people in New York and 12,000 people in Korea. Of those, 82.62% were still married to their partner, 81.63% claimed to still be active in the Unification Church and the couples had an average of 2.5 children between them...² that's 5188 children. So just from the year 1982 and just from marriages that occurred in NY we have an assortment of 10,000 people of whom 8100 are still active in the church.

And the UC married far more people in 2000 than they did in 1982.