> advanced clocks that predate similar European ones

I was thinking of the Antikythera mechanism, an analog computer/calculator from the 2nd century BC. There's a long gap in history from that time until Europe reached that level of technical sophistication in science and machinery.

A simplistic explanation might be: the fall of Rome led to the Dark Ages through political instability, loss of educational infrastructure, reduced trade, shift in cultural emphasis from classical science and philosophy to religion..

That reminds me of the Lost Libraries of Timbuktu, about the preservation of knowledge against time, wars, fires, and thieves. Not only technology but entire civilizations can get lost in time, like those pyramids in Natchez, Mississippi. Or the Lost City of Z, buried in the jungle.

In that sense technology - and the knowledge to understand and produce it - is always being lost to entropy unless we make an effort to keep it alive. Even then, shifts in economics or cultural context can make it impractical, unaffordable, or otherwise leaving no one to maintain it.

Even in my lifetime I feel like certain ways of thinking and living have been lost culturally. It's in the memories of those who experienced it, but after they're gone, there will only be footprints left in books, photographs, audio and video recordings, online archives and blogs.

Except then religion became responsible for philosophy's return and preservation.

the techicall ability to make the Antikythera wasn't lost - just the free cash to spend on such 'toys' that were a lot of effort to make relative to the value.

Another one: https://en.wikipedia.org/wiki/Sunstone_(medieval)