Thom Rainer at Christian Post writes of the "decline of the megachurch," by which he means that "big boxes" are out, and smaller worship venues are the wave of the future. Young people in particular are trending toward a preference for more intimacy than is offered by the anonymity of the megachurch.
That observation is not, in itself, remarkable. It's another reminder, though, of the entrepreneurialism of evangelicalism. The church business in evangelicalism is closely and consciously attuned to the market, and adapts to meet it.
It may not necessarily do so quickly--Rainer's observations have been true for some time--but it always tries to get there. It actively tries to discern the market and interact with that market. Evangelical seminaries teach courses about this. This is one of evangelicalism's greatest strengths.
Other traditions also respond to the market--that is, if there comes to be a critical mass of, say, Presbyterians in a certain place, they'll build a church. The Presbyterians are responding, in this case, to the "Presbyterian market."
Evangelicalism, though, is more in tune with the market as a whole, which, ironically, is more secular than the "markets" of individual Christian traditions. This is probably why evangelicals are so good at secular things, like electronics and commerce.
Indeed, in a way that evangelicalism probably doesn't recognize, and Paul Tillich wouldn't have anticipated, evangelicalism is, in its way, living out Tillich's "method of correlation," i.e. church and world in interaction.
This interaction is enabled by the paucity of visual symbolization in evangelicalism. Evangelicalism comes (somewhat circuitously) out of the Reformed tradition with its emphasis on the "pure Word." In the Reformed tradition, and in evangelicalism, all you need is a pulpit! This is why evangelicalism appropriated advanced electronics and sound technology. These aid in the advancement of the Word.
Martin Marty wonders if a tradition based on the market can long endure. Others might say that it is that tradition in particular which is most likely to endure.
Time will tell. My own opinion is that the entrepreneurship of evangelicalism is impressive in its ability to adapt. It enables it to respond to changing social conditions. On the other hand, I wonder how a religious tradition without aesthetics makes it over the long haul.