A Sermon A Week

Why should we have a sermon every sunday? What if a pastor stands up, goes to the pulpit and says 'I have no sermon for you today'? 

What is/should be/ideally has been the role of pastors? How much of it is expositing what the bible says and how much of it is modeling for the church what it means to be a man who is led by God, and out of that having sermons preached, may be twice a week? Shouldn't a shepherd be more of a man who is walking and leading the sheep and preaching being only one of the several ways he leading them? Or does a shepherd look at his responsibilities as, "If i give the sheep 5 whacks a day, give them to the waters once a week, then my responsibilities are over "

I find it hard to believe that every Sunday God wants the church to gather in a building, sit in the pews, and to listen to a pastor preach, and then go back home. I find it hard to believe that a pastor is called to preach every sunday. Don't get me wrong. There is a place for sermons, there is a place for preaching. However, as of today, I stand unconvinced that it needs to be done every sunday.