Comment by direwolf20

The ancient Greeks surely would have realised that an aeolipile could be used as a source of power, if they'd had abundant combustible fuel, a need for rotary motion, and no better source of it.

Newcomen engines are mere curiosities today, because we have better sources of power (better engines). In the past, they had better sources of power too (donkeys, wind, water, or human slaves). Newcomen engines, like all technologies, are only viable in certain economic environments. In all others they are curiosities.