This is a huge topic, David, but I’ll take a shot at it. I’ll probably cut it into a few pieces and then deal with them in more depth. I’m not a scholar so please take this with a grain of salt.
First, I believe the Church has a viable future in America. Our country is not on a great track morally, but I think there will still be many Christians here thirty or fifty years from now. There were Christians even in the decadence and promiscuity of ancient Rome.
Second, I think the Church in America should not be suprised if it stops being the center of Christianity. It’s arrogant for us to assume America will be the leading Christian nation in the future with the explosion of the Gospel in other countries such as China and Africa. Nothing is guaranteed.
You asked, “Is the church no longer a viable form of communication between Christians and the Lost?”
Yes and no. The true Body of Christ will never stop talking with and helping the world becuase the Body follows the Head (Jesus). But I believe that many institutions in America that call themselves Christian churches are not following Jesus. They have lost their saltiness. And that is a great tragedy.
If you don’t know yet, I’m writing a group of posts about controversial/interesting topics, and I want YOU to pick the topics for me. Check out some topics I suggested here https://jonathanbundy.wordpress.com/2010/04/05/new-series-of-posts-you-decide/
Per Sanguis 
jonathan
/ April 8, 2010Feel free to voice your opinion. That is what’s beautiful about this format.
Kells
/ April 8, 2010I was just talking to Thanne about this post and we spent some time specifically talking about your second point.
I know of a couple of people who have had conversations with me personally about the fact that Christianity is becoming more prominent in other countries.
There is such an influx of immigrants coming into America.
Over the past year I’ve begun to wonder about those chapel speakers who tell us that we must go overseas to spread the gospel. There is such a need here too and I believe we Christians (myself definitely included) need to step up the game if we are going to remain in the states after graduation.
Dad
/ May 9, 2010Jesus says in Matthew 6:13, “You are the salt of the earth. But if the salt loses its saltiness, how can it be made salty again? It is no longer good for anything, except to be thrown out and trampled by men.”
Does this mean there is no hope for those institutions that call themselves Christian, yet “have lost their saltiness”?