I disagree that perhaps the biggest challenge against Christians from skeptics, Jews, Muslims, and others is that the prophecies of Jesus and the writers of the New Testament failed. They all have their own failing eschatologies. If they don't believe, it's because of sin, not false logic.
Matthew 28
18 And Jesus came and spake unto them, saying, All power is given unto me in heaven and in earth.
19 Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost:
20 Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you always, even unto the end of the world. Amen
I got the concept from RC Sproul, who wrote a book “Last Days According to Jesus.” Sproul may have been the most important theologian of his day, having written so 80 or so books. I’d say his opinion as an apologist defending the faith is credible.