These exertions trying to make prophetic predictions have been going on for ages upon ages. All have been futile. Why?

When the apostles encouraged people that we should look expectantly for His coming was not unlike Abraham waiting for his inheritance in the land of Canaan. God told him it would be a ways down the road, and he died believing the words of God. Worked out in God's time. Don't accept my opinion on this?

Nevertheless, what remains is this: Jesus said,

“However, no one knows the day or hour when these things will happen, not even the angels in heaven or the Son himself. Only the Father knows." - Matthew 24:36, New Living Translation...

I really can't understand that in spite of Jesus clarity on the matter, people keep trying to outthink Jesus, God, and the Bible.