All this might have had less impact than you think. The real problem is that for centuries people (including the Greeks and Romans) held science (or "natural philosophy" as they called it) to be purely an abstract thing, and actually
sneered at practical application.
This seems astonishing to us today, but the truth is that "natural philosphy" was considered to have quite a different purpose than we think it has, and up until just a few centuries ago, any thought that science and technology were connected, or ought to be connected was accounted both vulgar and absurd.
For example, when the Roman writer Posidonius suggested that the arch and the use of metals were some of the humbler blessings that man owed to natural philosophy, Seneca repudiated these comments, which he regarded as actually an insult. Natural philosophy, he retorted, was not about teaching men to erect arches over their heads, or using metals to make things and do work. The "true" philospher cares not whether he has an arch over his head, or is exposed to the elements. He went on:
In my own time there have been inventions of this sort, transparent windows, tubes for diffusing warmth equally through all parts of a building, short-hand, whcih has been carried to such a perfection that a writer can keep pace with the most rapid speaker. But the inventing of such things is a drudgery for the lowest slaves; philosphy lies deeper. It is not her office to teach men how to use their hands. The object of her lessons is to form the soul. Next we shall be told that the first shoemaker was a philosopher!
These sentiments prevailed among nearly all intellectuals all through antiquity and the middle ages. Archimedes of Syracuse, who had one of the most inventive minds of history, disdained to apply his work. When the Romans invaded, and he had to put his genius to work defending his city, he was irritated at the need to pull himself away from philosphical speculation and sully himself with rude practical application.
So for century after century "natural philosophers" eschewed to put their considerable intelligene to any useful end, and instead occupied themselves with questions like: "What is the greatest good?" or "Is pain good or evil?" or "Can a wise man be unhappy?" etc. Abelard, the most respected philosopher of the 12th century stated that dialectic was the sole road to truth. In the words of one historian, " They filled the world with long beards and long words, and they left it as ignorant as they found it."
The man who did more to change that than any other was Francis Bacon, a 17th century Englishman. His writings effected a scientific revolution as significant as the industrial revolution. He preached simply that the proper function of science is search for fact and benefit people. Again, this seems so simple to us that it is too obvious to be worth remarking upon. But in Bacon's day the notion was quite novel. While at Cambridge, Bacon conceived a hatred for Platonic and Aristotlean schools of thought. Consider the following words of Plato regarding the constellations and stars:
We must get beyond them: we must neglect them. We must attain to an astronomy which is as independent of of the actual stars as geometrical truth is independent of an ill-drawn diagram... The true purpose of astronomy is not to add to the vulgar comforts of life, but to raise the mind to the contemplation of things which can be perceived by pure intellect alone.
Bacon likened the astronomy of Plato to the ox of Prometheus - "a sleek, well-shaped hide, goodly to look at, but stuffed with rubbish and containing nothing to eat."
For ages the views of Plato and Aristotle dominated "natural philosphy" and assured that it would contribulte nothing useful to humanity. Bacon started people thinking differently.
The problem is that as long as that old, fundamentally anti-scientific perspective was dominant, technological progress was always going to be slow and sporadic (as indeed it was for most of history). Heron might very well have realized he could put his engine to other uses. The problem was he had no interest whatever in doing so, and if he was a typical "natural philosopher" of his time, he might actually have been insulted by the suggestion that he
should. Even if he had, the anti-science mentality that prevailed then would probably have prevented the engine from being used as widely as it could have been, so in all likelihood the famous Roman roads would never have been supplanted by railroad tracks.