If one reads the Book of Revelation, one comes away with the idea that the author felt that Judgment Day would happen sooner rather than later. Exactly when it will happen has been a hotly debated topic ever since.
Of course, I have an opinion about that.
I think the author was correct in assuming sooner rather than later, but the final Armageddon was necessarily delayed until the angel from the east could round up and seal a quota of 144,000 truly righteous and godly people. The angel may be having trouble filling that quota.