Put simply, the development is a return to tradition and orthodoxy, to past practices, observances, and customary ways of worshiping. But it is not simply a return to the past—at least not in all cases. Even while drawing on deep traditional resources, many participants are creating something new within the old forms. They are engaging in what Penn State sociologist of religion Roger Finke calls "innovative returns to tradition."
P.S. Here's an example of the innovations.
An independent, nondenominational church of some 600 members, Trinity Fellowship is not the only evangelical congregation that is offering a weekly Eucharist, saying the Nicene or Apostles' creeds, reading the early Church Fathers, or doing other things that seem downright Roman Catholic or at least high Episcopalian.
Those are only generalizations about Catholic churches, of course. In the years I've been at St. Al's, I couldn't vouch for our saying the Creed at Sunday Mass more often than not. The only times I recall hearing anything about the Church Fathers was when I'm teaching Sunday School. Next thing you know the nearby Baptist Church will be proselytizing by promising the Confiteor, the Gloria in Ordinary Time, and kneeling.