When is the truth enough?

While i was in the Uk I bought a stack of books on issues relating to the demise of Christendom and the shape of the Church. A few years back I was considering doing this for a Masters thesis but threw it out the window
Anyway i have been doing a lot of thinking about this and talked about soem of the issues connected with it in a sermon on Sunday - One of my colleagues who heard the message said it had drawn up a few questions in his mind.
One particualr one related to the decline of the Church and all the rearranging refocusing and reimagening that is going on in an attempt to stop the decline. Surely the issue is truth not relevance.
I think he is right the issue in my mind is truth, but that must be followed by a further question what is the truth??? It seems to me that as the Church we can so easily forget what truth is or to put it another what the good news is....
The reimagening, rethinking and refocsuing is not just (I hope) playing with the seats but a genuine attempt to rediscover the truth of the gospel and seperate it from the dying corpse of Christendom.
While Christendom has offered the Church many good things (and bad) the gospel is not totaly wrapped up in it and I think could be removed from that context and allowed to be reimagined in a different context.