In reply to your question Charybdis, in the words of Count Iblis, the earth has had many rises and falls.
Basic history can tell you that.
However basic history that has been taught to us of our world and civilizations is mostly incorrect. Especially that of world history timelines.
And that of the technology the ancients possessed.
What happened to them you ask?
Look at simply history, many cultures that were once great often suffer from invasions from other cultures, thus waging wars often, civilizations are lost through being either conquered by their invaders, and thus much of what they had is destroyed or lost.
If you're wondering why there isn't much left over of those ancients technological hardware, think about it.
That kind of high tech stuff , if left to the weather and time, it breaks down until it turns to rust and eventually dust scattered across the terrain, if it has nor been kept somewhere preserved.
The stuff that survives are the simple things like stone instruments or tools, which then deceive archeologists and scientists to presume that , this was all the ancient peoples had to work with.
As civilizations went into ruin, degeneration set in, as those left forgot or did not have a thorough understanding or learning of their once great achievements, knowledge and technology.
Consider, if our civilization of today suddenly were attacked or invafed, and cities were destroyed and technology with it, and all that's left are the survivors , do you think everyone one of them would have a expert knowledge of all their former technology?
Only some might, but many would not know how to build a spaceship or a computer.
So, those who might know are limited and no longer have the supplies or materials left to rebuild the level of technological advancement they were once accustomed to.
So it is understandable how once golden civilizations are just as susceptible to fall , like we today are also susceptible to loose our standard of living/science/technology.
What we have discovered in our so called modern age, has simply only been re-discovered by what our ancients possessed from those ancient alien ancestors.
And we do not know the entire collection of what they knew.
There is indeed much more mind blowing things, that will one day be revealed.
