* technology accretes even if the quality of the average worker is declining across time. Thus tomorrow will still be better than today, at least from the point of view of things like technical advancement, regardless of what is happening within each person.
* population increases, so the smartest can still be smarter even if the average is declining
* Even if population is not increasing, improvements in communication and replication technology can mean that an increasingly smaller share of the brightest people anywhere in the world can design products that are replicated or simply assembled by masses of others, whereas in the past this required local designers. Think of how many people are truly needed to keep advances in jet engines happening. You have basically three companies that supply all the engines to the entire world.
* And one can even make up for the other -- e.g. in previous times all shoes were handcrafted, now they are mass produced. Thus a lower skilled person in a later period can still outproduce a higher skilled person in a previous period.
Now I'm not saying I necessarily buy the decline thesis. It's an intriguing thesis, basically that you can be pretty dumb and still thrive well enough to keep reproducing whereas in hunter gatherer societies you would have starved to death and so the population would on average be smarter due to the challenges they had to overcome. Maybe this is true, maybe it's not, but the objection that knowledge accretes does nothing to prove or disprove this hypothesis.
I cannot fathom how you possibly write this - surely you cannot be claiming that dumber and dumber workers develop better and better technology, or technology is some independent quantity that develops without human intervention, like a divine gift of some sort?
"a lower skilled person in a later period can still outproduce a higher skilled person in a previous period."
The last bloke operating the machine doesn't produce anything on his own, you have to compare the whole value chain, including the folks making the leather, making the tools and machines, etc. I am sure the old process includes plenty of people doing unskilled groundwork, although I would not bet my house on which way the dice would fall
That doesn't follow.
Civilization != technology.
And those previous generations weren't lamenting "kids these days have less technology than us", but "kids these days are worse in X, Y, Z" regarding ways of living.
Whats the difference between elusive 'X, Y Z' we can't define or measure, and 'X, Y, Z' that doesn't exist?
That's more of an argument that one can't really trust statistics. Or that they don't always measure what matters...
>Whats the difference between elusive 'X, Y Z' we can't define or measure, and 'X, Y, Z' that doesn't exist?
Well, we can define, and it does exist. Not sure if we can measure (not everything that exists can be measured in some meaningful way. Some things matter in qualitative ways).
So, for some concrete examples, the roman generations that followed the acme of Rome and steered it towards the decline had certain very specific characteristics. Less inclined to work for common good, more selfish, having less children (lamented by roman critics of the time, and which less to a big problem with economic dynamics, the army, and so on), more concerned with greed and self-indulgence, less interested in civic matters (which was the bread and butter of earlier generations), and so on.
If ancient Mesopotamians were the pinnacle of civilisation, and we were degrading for a hundred generations, we ought to be living in caves by now. It would be measurable in wealth, IQ, rates of murder, crime, literacy, etc.
Every statistics avaliable indicates that we used to be more ignorant, more violent and less literate. So this complain belong in the same box as:
"back when I was young we used to talk to school 12 miles, through a blizzard, uphill, both ways!"