http://thefederalist.com/2014/08/21/how ... easy-step/There's lots of speculation here, some I would agree with in principle, but I don't think all of his presuppositions are accurate. I'd disagree with the contention about Southern Evangelicalism being more focused on belief and not on "helping people." I'd be willing to bet that if you crunched the numbers of both volunteers, and dollars spent on those kinds of ministries, Southern Baptists alone would be doing as much of that kind of ministry as virtually all other Protestants combined. I've worked in one of the SBC's denominationally sponsored ministries that mobilizes volunteers, mostly high school and college students, for rehabbing and weatherizing homes for low income families for about 20 years now, with thousands of volunteers at over 100 sites every summer, the number of homes served over a 22 year period is now in the tens of thousands across the country. The disaster relief ministry of state conventions, coordinated through NAMB, is legendary. I don't know if you could even measure the extent of food distribution, hot meals and food pantry distribution, of the local churches, along with a very extensive world hunger relief program. I think the impression is created because the churches do a lot of local ministry on their own that isn't highly visible across the board. In the communities where I've lived in the South, Southern Baptists, and other "Evangelicals" represented the lion's share of that kind of ministry.
There's been a small numerical decline in the SBC since it's peak membership, about 3-5% total, though I wonder how much of that is due to an increase in the number of churches who don't send in their ACP. There's no question that Sunday School enrollment, which is probably the best measure of age group demographics, among 18-35 year olds is down from where it was two decades ago, though only by about 16%.
On the other hand, none of that is anywhere close to the losses experienced by the four denominations highlighted in the article, those figures occurring since those groups became open to ordaining gay and lesbian clergy. So it would seem that beliefs may have some effect on church membership.