They did not fall flat on the table. In verse three of the Romans text, Paul is asserting that if the Christian community responds to God's grace at work within it, what will then be the outcome is unity. However, Paul is not saying that it is simply uniformity that produces unity. In fact it is just the opposite. Diversity is the gift of God's abundant grace.
Grace is abundant, varied and is expressed in a variety of ways.
Yet, this multiplicity of gifts we all have is to be used to promote unity and not discord. The differences are not that some of us have spiritual gifts and some do not. The differences are that we have all been blessed with different spiritual gifts. It also must be noted that no one gift is better than another one. All gifts from the Spirit are equally needed by the Christian community.