Easy, there are people still being saved. That is the reason
why He tarries and is longsuffering. He is not willing that any should perish, but that all should come to repentence.
When the last one that will be saved is saved, He'll come back. No one knows when this is except God. I think we in the Western world see the culture becoming more ungodly, and think the rapture is certainly just around the corner. We tend to forget there is a great big world, and people are still getting saved all over this Earth.