Joseph,
    That is a great question.
I had wondered about that during the final part of the 1990s.
There were so many people that were so sure that it was measured from Jesus' birth.
From that came so many "clues", "hints", and pseudo predictions that the blessed hope was right upon us.
The year came and went, and the blessed hope had not happened.
Many were thus greatly discouraged by "rapture fever", and no longer diligently looking for the blessed hope.
A similar thing had happened after 1988, i.e. 40 years after 1948.
How much of their discouragement is laid at my feet?
Why did I keep "crying wolf", so to speak, over the years, hyping-up my friends, only to see them repeatedly let down?
Did I over and over, keep convincing people that the blessed hope was sure to happen this Jewish feast day, or on that anniversary?
I'm afraid that I'm not the only one who contributed to the extinguishing of the burning desire in so many people.
    Your point 2 passed a little less than a couple decades ago.
However, your points 3 through 6 would probably be at least ten years off still.