US Churches Lose 25% Chaff - Solid Churches vs. Flaky Churches

American churches have lost 25% of its church attendance over just the last ten years, but that's not too tough. . . because most of that is chaff. Catholics have seen 3 X the drop that Evangelicals have experienced, and Liberal Protestants have seen 2X the drop that Evangelicals have experienced. What makes the difference between a church with a solid truth foundation and that which is built of sand?