Yes, the evidence is forever being lost, which means
that any laboratory or observatory study of the supposed event would be ludicrous
and futile.
At what point will you say that [if the evidence is literally fleeing from you
and or disappearing] I don't have the means or ability to collect verifiable or reproducable evidence for this theory so I have to let the theory drop?

An analogy would be: A man drops a weight, and draws the conclusion that gravity
plays a role in the object dropping in the present [good assumption];
he assumes from repeating this experiment that gravity draws objects together in aeons past as well
[a reasonable but shaky assumption];
and therefore, he concludes that gravity will ALWAYS exist and will ALWAYS and FOREVER draw objects together.
[bad assumption]