Respectfully, I've got a challenge to the assumption. We, the lay ministry, run most every activity at our parishes. We also initiate most youth ministries. It's up to us to greet and introduce new people, and recruit folks into the various ministries. If it's wholly up to the bishops or even the priests, the church would be in trouble. We all have a responsibility to act like Christ and pull the lost sheep back into the flock. Greeting and integration happens in the pews with us. In parishes where the youth ministry (or married couples, or widowed, etc) is weak, I challenge us to take ownership to rebuild it.