Well, the U.S. is steadily becoming less Christian and less religiously observant as the share of adults who are not religious grows. *In order to reach people that no one else is reaching, you’ve got to do things that no one else is doing*. Leading people to become fully devoted followers of Jesus is more easily done in a warm, friendly, casual environment (with high-energy worship music) than it is in a cold, unfriendly, formal environment (with boring worship services).
I agree with a lot of that that, there is a place for entertainment, but it shouldn't be called a worship service. It's OK to have good music in worship. The problem with it, as practiced in the megachurches featuring popcorn & espresso especially, is that they never get beyond that and they never teach any of the harder teachings. It's all Dr. Feelgood BS. Really, aside from the divinity of Christ, most of it's very little different from what pagans believe(d).