[samatman]

I've long thought the answer is as simple as it is boring: their metallurgy just wasn't good enough.

Until the industrial revolution itself kicked in, metallurgy was a long and slow slog through incremental improvements in technique. There's no obvious way for a civilization to do a speed run on this process.

I don't think the printing press would have helped. The Chinese had movable type by the 11th century, and it didn't cause an industrial revolution.

The 'tech tree' argument that makes the most sense to me is that, specifically, demand for cannon, lead to enough improvement in metallurgy that steam boilers were something it was possible to construct. That being what really kicked things off. Hero's aeolipile didn't hold to a significant pressure, and if anyone had tried it, their vessel would have ruptured or shattered.

[mikewarot]

>I've long thought the answer is as simple as it is boring

Yep... without John Wilkinson's boring machine, you can't make a proper Watt steam engine.