Why Strict Churches are Strong

A Slate article examines The Power of the Mustard Seed. It comments on an economist's idea about why congregants at strict churches are willing to give up so much. Laurence Iannacone (the economist) postulates that an attendee of such a church follows the rules, gives up free time and some liberties in order to gain "a community of people deeply involved in one another's lives and more willing than most to come to one another's aid." Further, if the rules weren't so strict, there would be too many free-riders spoiling the product. On the other hand, if the rules are too strict (i.e. Catholicism and birth-control) the price of admission is too high and the church loses people. I imagine most people at my church would contend that they are willing to follow the rules because God has led them to. What do you think? Does it matter if there is a economic rationale for the church we attend?