[Chris2048]

Is the idea that it never moves, or that the cement will degrade by the time it does?

[Doxin]

I think the artist put it as "and then the last gear turns so slowly it doesn't really matter, so I cast it in concrete."

Assuming we're talking about Arthur Gansons "Machine with concrete"[0] of course. I quite like how a lot of his work seems to have a punchline to it.

[0] https://www.youtube.com/watch?v=5q-BH-tvxEg

[Piskvorrr]

It moves slowly enough that the wheel will approximately never turn enough to generate significant torque.