Ok, I understand.
I want to see evidence now...

Can you show me an example of one rare first edition book that has a date without the extra thousand years and also show me a later edition of the same book that has an an extra thousand years added? That is all that would be needed to prove that deliberate falsification of history took place.

I think it is very unlikely that every original book from the 1400's was destroyed. There must be some surviving texts that would reveal historical falsification with regards to the additional thousand years (if the falsification did indeed take place).