His attempt to explain the decline of American Christianity misses the real reason altogether. I suspect because he overlooked it because he is among those who are striving very hard to make the difference between authentic Christian faith and culture disappear by accommodation.
Gushee and his left leaning ilk want Christians to accept everything that matches the agenda of the liberal extreme of the Christian faith thereby eviscerating it of any meaning or significance.
In short, Gushee and those like him are among those who are speeding the decline of Christianity (or rather, the appearance of Christianity; the true Church is unaffected by their attempts since the true Church will have nothing of it) but they don’t realize it because they actually imagine that their acceptance of deviancy is good for the Church. Ha.
What Gushee and Held Evans and Bolz Weber and the rest of their kind need to ask themselves is the simple question- how well has accomodationism worked for the C of E? How well has it ever worked?