After rebuilding the walls of Jerusalem, ‘the city was large and spacious’, but there were few people in it (Nehemiah 7.4).
There is a similar situation in many churches in our inner cities. There are small congregations in buildings that quite simply need more people. It would be wonderful if these were filled through conversions, but that is not happening. No doubt some churches are in-grown, but most churches I know are actively evangelistic. What these churches need is more people with the attitude, gifts and money that will strengthen them in their mission.
The answer is not simply church planting. One of the most encouraging developments in recent years is the planting of new churches. While sometimes I think this is a bit of a fad that is seen as a cure all, there is a tendency, at least in London, for many of these plants to be the ecclesiastical equivalent of a boutique hotel with a niche congregation of people of all one type. Nevertheless it is good news that churches are being planted.