Theories have been put forward that, for example, the pottery was less "beautiful" because people had been busy surviving the crises. As we know now, the opposite was often the case (but not in general). We cannot distinguish between the ancient periods by simply judging about the artistic quality of the remains we found.

That's an interesting question that I sometimes ponder: whether hard times means good art, and rich times means decadent art. And whether the opposite is true for the sciences: whether riches means flourishing of the sciences.

For instance I know that in the former Soviet Union, art was great. Movies, novels, music, everything flourishes, due to the oppression. But now good art is scarce.

Also, ancient Greece flourished both scientifically and artistically when it was a 'superpower', whereas now they may as well be a third world country.

I must say the glass artifacts and the faience are most impressive. Really masterful. I wouldn't be able to tell them apart from modern ones.