Mark Twain famously wrote in a note: "Reports of my death are an exaggeration."
That's about right when it comes to the Pew study too. If you saw any of the news regarding the report, you know that the "Nones" are on the rise and the "Christians" are in significant decline. Some of the reports stopped short of including a smiley face, but it seemed the glee was there.
But what is actually there in the report? Consider the following graphic (you can click on it to enlarge it):
What you see displayed is a study from 1972 to 2014 charting the percentage of the population of the U.S. that is considered church-attending. The green line is evangelical, the red line is Protestant Mainline. The last time the Mainline congregations had a greater percentage of attendance that evangelical church was 1972. The line explains itself.
There's no glee. Either in the demise of the Christianity generally or the precipitous decline of the mainline congregations. But there is hope. What I consider nominal and cultural Christianity seems to be shrinking (and no, I'm not saying all those Mainline churches are nominal or cultural Christians, though their denominations have shifted away from biblical teaching and standards officially). Churches that are committed to the Gospel, to the declaration of God's Word, and to the standards found therein seem to be very much holding their own.
Is there room for improvement? Goodness, yes. But the sky isn't falling, Chicken Little.