It's true that some parts of the world (like much of Europe) are becoming less religious, in spite of their deep roots in the Christian faith. It's not universally true, however; in other parts of the world (such as Africa), thousands are coming to Christ every day.
Why has unbelief grown in some places? No doubt many reasons could be given. Sometimes it's because Christians have failed to share their faith with others. Sometimes it's because of attacks on the Bible and its message (including its call for moral purity). I often think of Isaiah's words: "Woe to those who call evil good and good evil, who put darkness for light and light for darkness" (Isaiah 5:20).
But often it's because people have become preoccupied with material comfort and success, believing the only thing that matters is life right now. They've become secular and materialistic, never thinking about God. Yet down inside, their lives are empty, because secularism can't satisfy the deepest yearnings of the human heart.
Can this happen here? Yes, of course it can. We see things happening in our society that we could never have imagined a few decades ago. Pray for our churches and their members, that they may boldly proclaim Christ. Pray too for yourself, that God will help you be a witness for Christ to those around you. May the Apostle Paul's words become true of us: "I am not ashamed of the gospel, because it is the power of God for the salvation of everyone who believes" (Romans 1:16).