What Is Church For?

What is the church for?
I've had a series of rich conversations over the past little while that all come round to some variation on that question. What is the point and purpose of this enterprise that we call the church?
These conversations -- with friends and colleagues both locally and spread a bit further afield, some Presbyterians, some not, some ordained, some not -- have not typically begun with the existential question of "why church"?
Typically the conversations have begun around an aspect or program of the church that needs attention. For example, my Presbytery's camp and conference center is about to be put up for sale and that has occasioned considerable conversation about that type of ministry and program. On a completely other note, the recent change in my denomination's stance on ordaining gay, lesbian, bisexual and transgender people to church office has prompted conversation among progressive friends about what's next for congregations or networks that have worked long and hard to see this change. Elsewhere in the mix, I've had a couple of rich conversations about worship and spirituality.
Somewhere along the line in each of these conversations, in a manner appropriate to the particular focus, someone will ask some variation on this question: what are people looking for?
Perhaps that is the common lament for leaders in shrinking institutions.
We seem to believe that if we just knew exactly, precisely, programmatically what people are looking for then we could supply it, kind of like Ben & Jerry's knows that people are looking for ice cream so they supply it.
It makes sense, in a consumer culture, to assume that if you can identify the point of demand then you can create a supply to meet it. And that does give an answer to the existential question: the church is for supplying whatever it takes to meet the demands of the people under the broad heading of "spiritual products and services."
One could organize a more or less efficient supply side of this equation by drilling down a bit into "spiritual demands" to clarify the nature of those demands. From this perspective, the great challenge to the church lies in perfecting market research and product development in the spiritual marketplace to meet the growing market of the "spiritual but not religious."
That is no doubt true to some extent, and we should get much better at asking such questions. Still, I can't help feeling that there is more there, and that the ways we frame and word the questions are both profoundly important and poorly understood.
Perhaps it is the difference between doing market research and telling parables. The kingdom of God is like a mustard seed ... the church is like kudzu.
So, what is church for? Anybody ... Bueller ...?