What is that conclusion?
The conclusion is that the particular activity (activities) undertaken when the church meets is less important than the goal (or outcome) of that activity (those activities). That is, whatever we do when we get together with other Christians (activities) should have the goal / outcome of building up one another in maturity in Christ.
Eric gives a good summary:
This indicates that content of gatherings is not nearly as important as the attitude and motivation of those present. If the goal is edification and church people strive for this, then any of a wide variety of things could happen – maybe preaching, maybe teaching, maybe scripture reading, maybe testimony, maybe prophecy, maybe speaking in tongues, maybe the sharing of the Lord’s Supper, etc. However, if edification and the sirring up to love and good works is not the goal, then it doesn’t matter what we do because it won’t be biblical.
A good scriptural example of this can be found in 1 Corinthians 11:17-22 (actually 11:17-34, since the whole section is about the same topic). In this passage, Paul points out that the Corinthians are doing the activity (eating and drinking), but that the result is not the Lord’s Supper because they are not concerned with one another. (Note, there is no “doctrinal” issue involved in Paul’s admonition, only relational issues.)
What is the church’s primary activity? Whatever leads to mutual edification. And, yes, as a commenter pointed out, mutuality is necessary for maturity.