I know what you're saying and I agree that we are currently dealing with this particular beast currently, but it doesn't begin to supplant the idea of a final Antichrist reiterated in the New Testament as well as many other prophecies. We will have to deal with this beast and the chastisements that follow.

The triumph of the Immaculate Heart fits rather well I believe with the "6th age" of the church (Philadelphia), which may or may not terminate upon the death of the Emperor, and the 7th and last age of the "Antichrist" which from all sources I've seen indicate will only last about 3 years but will be so terrible and complete that people have to flee their homes and hide in the wilderness to escape being snatched up. He will be so seductive as to perform miracles set to rival Christ himself... even false resurrections! Perhaps overconfident from the success of the previous age, people will wholeheartedly abandon the Church even more than they've done today.

There's also the concept of Elias and Henoch coming back to earth to testify against him. The church has seen many figures of the antichrist, but the worst is reserved for last.