[marcosdumay]

Commercial metalworking stayed around all the time until today. It only increased and improved. (It's made of bronze, it's not like bronze working was lost.)

The tooling may evidence some kind of regression. I really don't know what kind of tooling was needed to create this, although gears by themselves and high precision in a single mechanism do not say much. From the looks of it, this devices requires a lot of theoretical knowledge, but not so much practical one (but that's an uninformed opinion, if you have information, it would be great). The theory was not lost in any way.

[hasmanean]

Don’t forget the fact that the mechanism used a model made by Hipparchus, but after Hellenism the Greeks adopted the Ptolemaic geocentric view of the cosmos with epicycles and stuff.

Epicycles delivered more precision but at the cost of much greater complexity. Ultimately it took Kepler to simplify it even more through his iterative equation though I can’t imagine how to turn that into a mechanical model.

The Antikythera mechanism was possible because of the simplicity of the underlying solar system model that lent itself to easy implementation by gears. It’s much more elegant than even modern methods of computing orbits. That’s the main surprise I find in its design…how much they could simplify it (and not how complex the mechanical construction is).