Attendance at worship services alone will not be sufficient glue to generate commitment. While it is not a rock solid principle, there is a likelihood of real involvement if each person has some way of expressing their faith meaningfully within and through the church community. This may be through participation in a small group, or the exercise of some ministry in association with others. Church, like any other corporate activity, can become a spectator sport. Some churches are simply out of touch.
Services are unimaginative, dull and utterly predictable.
Erratic attendances and the constant movement of people in and out of the church does not ring a bell for anybody in the leadership. This is not always the pastor's fault either. Resistance to innovation, little or no opportunity for participation and a lack of life and warmth will cool off the keenest of us. Too many churches lack an effective process for following up newcomers. There is no point being overly critical of new faces who fail to show the next Sunday.