[attacking remark removed-moderator]
Let's start unpacking your assertions.
1. The meaning of "no evidence." Historical and archaeological conclusions work a bit like a legal case. Imagine a murder trial. We know there's a body, but "Whodunnit?" Nobody witnessed the murder so far as we know. Yet we find clues. We look at whether anybody had a motive for killing the victim. We look at whether anybody with a motive actually had the means to carry out the crime. Is there an alibi, if so? Were there eye-witnesses who would testify that they saw somebody with a motive and the means running away from the crime scene with blood on his shoes? This person may become the defendant. We weigh the evidence and try to make logical inferences. Depending upon the standard required for the charges in this case, the jury will have to decide whether the defendant is guilty or innocent based upon "the preponderance of the evidence" or "beyond a reasonable doubt."
Similarly, nobody living today was living 10,000 years ago. We have to base our assumptions about the origins of astrology based upon the preponderance of the evidence; or, if we are of a cautious nature, beyond a reasonable doubt.
And you will find careful archaeologists and historians writing conclusions like, "There is no evidence that X artefact was invented before date T." "The oldest date known on an existing artefact of type X is ca. 700 BCE." Then these scholars might cautiously speculate further based upon oblique lines of evidence or comparable discoveries.
But the "burden of proof" (to use another legal phrase) would be entirely upon someone to produce new evidence that a phenomenon or artefact existed long before there is any direct evidence of it, before we find the necessary antecedant conditions, or before we find any comparable developments.
Does evidence get destroyed through the passage of time? Sure it does. Moreover, some evidence that we would dearly love to find today doesn't exist because nobody bothered to record it at the time. Yet oftentimes you will find collateral types of existing evidence that allow you to make cautious conclusions about the presence or absence of a given phenomenon at a given time and place.
To use your Japanese nuclear bomb example, some archives destroyed in the blast cannot be reconconstructed. But we might look for a lot of collateral information in Japanese cities that were not destroyed during WWII.
2. Your "investment" in Vettius Valens. I didn't flatter myself that you would interpret a chart using Valens's techniques just to suit me, JA! LOL! Rather, since you revere his work, I thought you might have applied it on another thread on which I haven't participated (lots of these!) and that you might simply provide a link, if so. [attacking remark removed - moderator] If you have never applied Valens's techniques to horoscope interpretation either on this forum, or elsewhere, then I might question the basis of your strong confirmation of his techniques, however.
In my previous post, where did I "demand" that you produce a Valens type of reading? You seem to be putting words in my mouth. And no need to lecture me about people volunteering their time to read people's charts, JA! Many of my posts are of this nature.
Where did I ever deny the considerable importance of Valens work? I haven't and wouldn't. But hey, JA-- I am entitled to my own opinion, even when it varies from yours.
In terms of Valens predicting the native's length of life and manner of death, as we know, these were huge concerns in ancient times. The average life expectancy was low; and kinship was so important to people and politics so perilous for the elite, that the death of the pater familias could be a huge blow to a big household.
The fact that I personally choose not to deal in "death clock" astrology hardly means that I think badly of Valens for doing so. It simply means that a chunk of his work has no bearing on the kind of astrology I choose to practice. And yes, I do poke fun at his work from time to time. (As in "fun", JA.) Scoffing? Nah. Though I would love to take you by the hand and point out particular passages that are kind of laughable today. You might laugh at them, also.
But gosh, JA-- why is it that you are unwilling to lighten up about Vettius Valens? Why why let inferred criticism of him get your goat?
3. Replacement of older academic theories by newer ones. Yes, absolutely this happens a lot. It also happens in society as a whole. And so it should. For example, social scientists in the 19th century had theories about why women or people of colour were inferior to white males. Today we see through these prejudices for what they are. Also, as new and unexpected evidence comes on line, it causes scholars to rethink their previous theories. Some theories are a lot more robust than others, however.
[off topic goading remarks-moderator]
I have a mental image of it busting into a room, chest puffed up proclaiming "I'm here!!" , strolling around knocking everything down. Hmmm...modern or traditional....I don't know which one I prefer!! 
!
should be fun/interesting!