It is not a foregone conclusion that a church in any given place is a random sampling of the community. If you are in a city of 10,000, and you look at a church of 100 (1%) or even 1,000 (10%), it’s not altogether certain the makeup of the church reflects the make up of the community.
Look at some key areas to prove this: mixture of marrieds vs. singles? Mixture of age ranges? Mixture of professions? Mixture of ethnicities and languages?
If a church does not reflect the community it is in, the things that drive the church (needs, desires, values, etc) will not be reflective of the community, either. What drew the people in the church to the church is not necessarily what would draw the rest of the community.
Outreach programs that will draw the rest of the community will not necessarily be immediately appealing to those in the church.
You need apostolically gifted people who are able to function ‘on the edge’ between the church and the community, and reach into the community–and those who are successful will likely be very unlike the church.
You have to make space for people unlike you if you want to reach into communities that are unlike you.