A great deal has been made in recent months about the crisis in American Christianity. A fairly recent Pew research poll concluded that while most people believe in God and self-describe themselves as Christians, many of them are no longer affiliated with a church or other worship congregation. While there are many reasons for this, two primary ones tend to sum up the problem.
Attempts to appeal to the masses
This is a problem found in all churches but it's a huge problem in the mega churches. To keep the seats full there is little emphasis on sin and salvation and a lot of emphasis on entertainment, the prosperity gospel and making people feel good about themselves. When sin is discussed, it's always alluded to being something that someone somewhere else is doing. Salvation is assured no matter what kind of life you are living as long as you write a check and keep the coffers filled. Church here is about the social aspect of religion and there is very little worship of God.
Attending these churches as an act of worship is all but pointless and attendance is falling for the simple reason that many people don't see a reason to attend. They aren't learning anything, their spiritual needs are not being met and they don't feel the need for validation of their lifestyle choices. . It's an exercise in entertainment and to be seen by others. The doctrine is so maligned and watered down that it has ceases to be a recognizable form of Christianity. Tolerance of any and all behaviors is considered more important than the message of salvation. These churches, as well as those who attend them, are intent on remaking God in the image of man. They are playing church.
Failure to appeal to the masses
On the other side of the coin you have churches that fail to appeal to the masses because they do hold strictly to their doctrine. Sermons are preached that admonish those sitting in the pews as much, or even more, than those who are not present. Sin and salvation messages are preached and there are moral absolutes.
These churches are often accused of being 'mean' and not tolerant enough. The problem is that society has become so liberal minded that it often forgets that some things are simply not open to a majority vote. God has not changed just because society has shifted. Those who are looking for validation of lifestyle and behavior choices that are contrary to orthodox Christian beliefs will not appreciate churches that insist man attempt to remake himself into the image of God. Because the doctrine in these churches is not willing to shift with the political and social climate, they will be labeled intolerant, mean and bigoted.
These two primary issues are why church attendance is declining in America. All other issues can fall somewhere under the two headings. This isn't going to change. God never changes nor do His standards. Current society refuses to accept this uncomfortable truth. Until it does, attention in churches will continue to decline.