I just checked, this isn't true. I've Google Calendar entries from over 10 years ago. Where did you get the idea that they delete anything older than 2 years?
(side note: the title of this post is a little sensational imo. the past has always "disappeared". Don't forget that you will die some day and eventually there will be no trace of your existence)
Now that I'm looking for it, I don't see Calendar listed as one of the products controlled here, but it might be grouped under GMail or something.
I lost a bunch of emails from my now passed mother which I went to go look for, and found out that Gmail chopped history.