Falling away from the faith. The great falling away does not mean that there will not be church at all. Rather, it means that there will be a great backsliding from the original faith, departure from the truth, living in error and ungodliness.
"For the time will come when people will not put up with sound doctrine. Instead, to suit their own desires, they will gather around them a great number of teachers to say what their itching ears want to hear. They will turn their ears away from the truth and turn aside to myths." - 2 timothy 4:3-4
If the churches were parked full and yet, they are living or dwelling in sin, it is as if there is no church because what you have left is not a church. The church of our Lord is that which is build on the sound truth. The devil want to corrupt and compromise the church. This may not be binding and loosening, but the fight to preach restoration and revival. If the gospel is compromised, then, we don't have church anymore.
The devil is already in the church waging war against the Saints.
"Dear friends, do not believe every spirit, but test the spirits to see whether they are from God, because many false prophets have gone out into the world. This is how you can recognize the Spirit of God: Every spirit that acknowledges that Jesus Christ has come in the flesh is from God, but every spirit that does not acknowledge Jesus is not from God. This is the spirit of the antichrist, which you have heard is coming and even now is already in the world." - 1 John 4:1-3
The Antichrist is already in the world trying to make the church weak through wrong teachings. The church has become worldly and carnal. We must resist the devil through preaching and practicing the truth.