"Silk reminds Catholics that the problem of disaffiliation is not confined to Catholics. Evangelicals and their mainline Protestant cousins also suffer from defections."

Although he's correct in saying that Catholics and mainline Protestant churches have been losing membership, he's wrong to say the same about evangelical churches. The Pew polls showed them staying level and nort declining.

What is a similarity between the RCC and mainline Protestant churches that doesn't exist in evangelical churches? The former have been moving away from traditional teachings (at least under Francis), whereas the latter have mostly stuck to the fundamentals. As the article points out, there maybe other factors involved, but this might be one of the more significant.