Questions about Heron's engine are regularly posted here, often because of the suggestion ( made by, among others Howard Zinn) that the Greeks had slaves to work for them and never bothered. I posted an answer here a while back. We don't know about Heron's prowess as an engineer. If he ever did any measured drawings and material specifications for his devices, they have not survived. The drawings that you usually see accompanying them today are from the past several hundred years. The short answer is that , in order to do actual work, not just be a toy, the Aeolipile would have had to be pretty big, able to contain considerable steam pressure, and spin on bearings that had good seals. The Greeks would have had a very hard time doing all that. So, other than as a small toy the Aeolipile was very likely never built.

Nor did anyone try to make a high-pressure steam vessel when real steam engines began to be built. It was too difficult, too dangerous. When Newcomen created the first practical steam engine in the early 18th. c., it had very little steam pressure. A weight pulling down on the pump beam lifted the steam piston, drawing steam into the cylinder from the boiler. That was condensed by a spray of water, and the collapsing steam created a vacuum. Because of that, atmospheric pressure then pushed down on the piston to make the only work stroke. The only thing under any stress, therefore, was the steam cylinder, which was under at most 14 pounds/square inch pressure from the outside. The engine was enormously inefficient- for one thing, because the whole cylinder was alternately heated and cooled, lots of heat was lost. But Newcomen engines were first set up to drain coal mines, and the fine coal dust that could not be transported and sold provided a cheap source of power. The earlier mines did not reach levels low enough to require a large pump- reaching those levels came with the clearing of English forests and the exhausting of "sea coal" and coal seams close to the surface. So, you could say that, before around 1650, there was not that much need for a steam pump, and so no need to supply one with the huge amount of fuel it would have required. This is not to say this was all organized, like there was a Dept. of Industrial Planning working for James I, rejecting plans for steam engines. Iron forging and brass casting technology had advanced enough by the 17th c. to allow one to be built, perhaps earlier, if anyone had wanted it. But the coincidence of the need for a large pump with the fuel to feed it is pretty important.