So, Hero of Alexandria is said to have invented the aeliopile in the first century AD. This, as far as I can tell, is essentially a working steam engine.

That being the case, why did it take nearly 2000 years for the industrial revolution to start?

I grant that they may not have known about coal, but is the energy density of the fuels they had available really so low that they couldn’t have run anything using engines? I mean, they must have had flammable oil, and could have distilled ethanol with the tools available to them.

Why was the aeliopile a curiosity, rather than the prelude to a Roman industrial revolution? Why didn’t they use it for anything significant?

Edit: my title may give the indication that I think “first century AD” and “100sAD” are the same. I don’t.