I just threw an approximate guess of 2-3k years. If it's 6k, more to my reasoning: there's been so much time and effort to learn those that proper principles are now well known and can be taught and applied repeatedly, reliably, affordably.

I don't think people have changed at all, and I didn't say it anywhere above, so I don't understand why you assume I think people have changed significantly.

Our knowledge in a few areas has grown significantly though (read: crafts, science and technology). I don't think anyone reasonable would disagree, but who knows.

No offence intended, I just noticed a lot of those numbers where fairly low. Like where you say dentistry is century's old which is clearly true, but "Remains from the early Harappan periods of the Indus Valley Civilization (c. 3300 BCE) show evidence of teeth having been drilled dating back 9,000 years." http://en.wikipedia.org/wiki/Dentistry

So it's 90+ century's old. Which is one of those, wait what? moments for me that I like to share.

That's fine. I don't know the exact details of all those disciplines, I like history, but my knowledge of it is limited. I was within reasonable orders of magnitude of the real dates, or lower, which helps my argument that software engineering is incredibly young, which is the whole point :)

The earliest known megalithic construction site is 11 thousand years old: http://en.wikipedia.org/wiki/G%C3%B6bekli_Tepe

The problem is that there has been no continuous architectural tradition. Most of the advanced Roman building methods were completely lost around the 5th century (concrete was not rediscovered until the 18th century). The Egyptians around the time of Cleopatra had no idea about the construction techniques used to build the Great Pyramid of Giza (this is why the Greeks assumed the pyramids were built by slave laborers). This is not surprising considering that Cleopatra lived closer to the first moon landing than she did to the construction of that pyramid.

At the smaller scale. There is a continuous tradition in home construction over that time period. Further, Japan for example had an independent tradition unaffected by Rome's rise and fall.