There are enough people to go around without churches needing to compete head-to-head against each other. The director of the Center for the Study of Religion at Princeton University, Robert Wuthnow, said the basic makeup of the U.S. looks like this:
• About one in four of American adults is devoutly religious;
• one in four is secular, and
• the remaining half is mildly interested about religion.
In other words three out of four people are not committed church-goers and, thus, the Church is not a zero sum game. By "zero sum" I mean that for one to gain, another must lose an equal amount. Some folks practice church this way, effectively ignoring evangelism and depending on transfer growth. Many programs in churches are geared to appeal to those who already have a developed interest in Christ, but might be willing to upgrade. But the Church, no matter where it's located, is almost certainly sitting atop an untapped reservoir of unchurched and postchurched people, waiting to be evangelized or restored.
If every congregation sought out the lost as they're supposed to, every church could multiply and max out instead of operating at half strength.
In regard to "sheep stealing," the practice of targeting practicing Christians and luring them to your own congregation, we just don't go there. In many respects it's unethical and you're really not going to get the people the church family needs (you'll just attract more folks with consumer mentalities). Instead of stealing sheep, however, we do plant green grass. We want to create as healthy and functional a church family as possible: instead of overloading you with programs or cramming our own idiosyncrasies down your throat, we try to model genuine, earnest, and consistent Christianity. We won't necessarily wow you, but I believe we'll have a profound and lasting impact (it's the same approach I have to parenting – no flashy gimmicks, just consistency and integrity). I believe that Christians with dysfunctional church experiences (the postchurched or soon-to-be postchurched) will be drawn to this.