What's the Difference Between These Two Churches?

Here is another question for my Great Commission and Church Planting class: How do you view the two churches I describe below? Do you view them as very different?

You walk into the first church and begin to notice that all the people there are old. Say 70 years old or older. The pastor is likewise elderly. You begin to look for another young or middle-age family like yourself. You don't see any. What do you think of this church?

You walk into another church the next week and there are tons of children running around. There are many youthful looking families. The pastor looks young too. The place is bustling with activity. In contrast with the church you visited last week, you don't notice any elderly folks. What do you think of this church?

A common first impression of the elderly church is that it is dying, not reaching out to its community, and somehow it is "bad." The younger church seems vibrant and alive, and it is somehow "good."

But why would we think of the church this way? What if the elderly church happened to be in the middle of a retirement community? And why do we think that a church with no elderly people is better than a church with no young people? Don't both churches have a key missing demographic—in other words, both are lacking something they really ought to have?