Nobody here is trying to claim that ancient humans were not intelligent people, SkyWriting.
However, that doesn't mean that your prototypical 'Adam' was, well, anything. Indeed, it is far, far more likely that 'Adam' was a propagandist myth rather than a real person. In order to present him as a 'real' person, you have to present him as being a superman, far superior to us 'normal' humans, and that human IQ has been declining ever since this supposed 'fall' (because nothing can be better than the first human who ever lived - as if we were some product churned out by mass production).
Let's take this IQ graph you presented, which projects a considerable loss over time (from an average of 92 in 1950 to a projected average of 84 in 2100). Seems pretty significant - but not in the way you think it is. The reason average IQ is dropping is not because of technology, but because less intelligent people are more likely to reproduce.http://www.upi.com/Health_News/2013/05/23/Last-century-Western-nations-lost-an-average-14-IQ-points/UPI-77081369362633/?spt=hs&or=hn
In short, if high-intelligence people tend not to reproduce as much as low-intelligence people, then naturally, the proportion of low-intelligence people will increase and the average IQ will drop.
Indirectly, this is due to increased education opportunities. Since education increases IQ
, countries with a standardized system of education tend to have more intelligent people (especially if those countries also have a longer period of mandatory education). So countries which do not have such a system (which would include most third-world nations) are going to have noticeably less intelligent people in them. And it is in those countries where the population is increasing the most quickly.
Since those countries are pushing worldwide population growth, that means that their populations will have a lower IQ on average, and thus the worldwide average IQ will drop.
And there you have it. A far more believable explanation for the reduction in average IQ than some mythical genius proto-superman who could do anything (yet, strangely enough, did nothing but farm and have children).
By the way, the statements in Genesis you cited about people who were the 'ancestors' of those who did various things (you listed those who play stringed and wind instruments, and blacksmiths and those who work with metal), are more of that same propaganda. It's pretty obvious that the Hebrews, like many other cultures of that time period, wanted to believe that they were the greatest civilization ever to live, and thus made up history to suit what they wanted to believe, rather than what was actually true. So naturally they would claim to have among their number the fathers of various disciplines (like music and metalworking, and others I would imagine).
You can choose to trust the propaganda of the Bible if you want. As for me, I'll stick to what we can actually discover about the past, rather than relying on a clearly biased source.