[To put this post more succinctly, I am sceptical of the extent to which lack of capitalist investment needs to be explained. Taking into account the difficulties of investment in later periods, it seems to me that the need to explain anything is the result of looking back rather than looking forward. Without foreknowledge of what capital investment would do, the low returns that could have been acquired by investment in this era seem like a sufficient explanation. It is not that the social system, or slavery, or anything else had to be particularly productive, it is sufficient that the expected returns from investment would be low enough not to give someone an incentive to invest rather than consume. It's like the diminishing returns in the Solow growth model, at some point, despite knowledge of some future higher income, the margin of greater future income becomes low enough that it is unappealing relative to consumption now. That exponential growth and technological development would occur as a result of these advances is obvious in hindsight, at the time I doubt this would be at all obvious, even assuming a more modern mindset. Also, it needs to be noted that businessmen tend to be basically conservative, they certainly do some investment that is oriented towards innovation but this tends to be along channels that are fairly well established. They rarely break truly new ground. The difficulty with any technology is almost never with producing the various disparate pieces and knowledge necessary for their implementation, it is bringing them together and making them reliable enough for private investment to occur. This would be far more true in classical times when the sum of knowledge was so much less and the opportunities for disparate ideas and inventions to be put together in new combinations so much fewer.]
I've been on a bit of an ancient history reading binge recently, currently Peter Green's Alexander to Actium. Excellent book on a poorly known period.
But what I wanted to get at though were some of his comments on the development of technology and the Greek attitude towards science. I don't really disagree with the basic premise that a major problem with translating Greek theoretical advances to real world applications was the elitist attitude that kept Greek natural philosophers completely separated from actual craftsmen. What I have a bit of trouble accepting is that across the entire Hellenistic world that there wouldn't be sufficient eccentrics to have at least a few islands of innovation, which theoretically would be able to lead to technical advance and ultimately to these innovators being able to outcompete their less eccentric brethren in in the marketplace if this was all that was blocking them (I have in mind some better documented societies such as rather innovative exceptions in Hapsburg Spain and Austria-Hungary, these had comparable elitist attitudes but did have model farms and other innovative exceptions, there were fairly good structural reasons why their advances didn't spread to the rest of their societies though, it wasn't simply aristocratic attitudes).
Rather, I think too little emphasis is given to the economic constraints faced by any innovator. Of course, it is true that the Greeks (and later Romans) did have many of the isolated inventions that if combined could have replicated many of the advances of the Dark Ages, and Middle Ages at least (saying the technology was there for an industrial revolution seems off to me, though I've heard it). However, the existence of isolated technologies is not enough for an entrepreneur to be able to use them industrially. In every society there's a lot more that can be done on a small scale than can be a large scale. Think of the advances we use for our most advanced fighter jets, and then think of the relatively primitive planes that we fly in day to day, to just use the most clear and accessible reference I could think of. We have the technical capacity to make these planes reach some pretty impressive speeds, we lack the technology to mass produce these things at a low enough cost for the consumer.
I think this is largely the problem faced by a hypothetical Hellenistic entrepreneur. It probably was possible, and it may even be the case that there are undiscovered instances of, Greek merchants using some ingenious inventions to up the productivity of their workers. However, often on the same page as talking about the great possibilities of Greek technology, severe shortfalls are mentioned, such as the poor quality of metallurgy. From Braudel, I remember reading that during the early modern period there was a shift in capital investment from largely operating capital to fixed capital (if I am remembering the proper terms), this was caused to a large extent by the increased durability of materials used, with the lower cost of metals and increased strength being the biggest part of this. Hellenistic metallurgy was very primitive, just using Green he describes it as being an iron bloom that had to be pounded to make a small amount of wrought metal, tempered steel was impossible.
The point being, in these conditions why would a Greek merchant, even an eccentric genius, invest capital in production? There probably wasn't a reliable source of high quality cheep metal, what was available high quality was expensive, that which was low quality wouldn't last. Drawing from my memory of medieval capital investments, they sought to minimize the metallic components of devices such as waterwheels, given medieval conditions it was expensive and difficult to replace when these wore down. If this was a problem then, how much more of a problem would it have been in the Hellenistic age? Not to even mention the lack of technical manuals, low literacy rates, and the likely even more marked separation of the propertied class that would actually know the basic science from anyone making direct production decisions (after Green I hope to look up some more books on ancient economics, I am running with my impression here that estates and other properties were run through hired managers, who would likely be less well read than their masters, here, I am not certain this is accurate in regards to economic management of the time).
In short, while I don't want to make it sound like Hellenistic merchants would have thought in these terms, the opportunity cost of employing capital was probably higher than that of other activities in this period. I'm running off admittedly thin data at this point, but my impression is that with poor metals, a shortage of highly skilled craftsmen, and a lack of quality control mechanisms to insure regular access to well machined parts (while there is evidence they could be produced, were they produced in sufficient quantity and at sufficient low cost for someone to accidentally stumble into efficient capital investment? I doubt it). I don't doubt that elite beliefs were a significant barrier to investment, but even if this wasn't the case, I doubt that given conditions investments would have paid off anyway. While we know today what was possible, in an environment where this wasn't known, would it really have looked like a good investment to build machinery to replace labor when the parts were of poor quality, wear was likely to be great, and any skilled craftsmen to maintain it would have been in fairly short supply (I am assuming this, I don't actually know the numbers of top craftsmen in the day, but given low agricultural yields it doesn't seem like there could be too many of the very best in any craft). This isn't even to mention the uncertainty of the political circumstances. Why build a somewhat crappy watermill at great cost when it's likely to be destroyed in the constant warfare of the period, better to invest in land which even if ravaged in one year can still be used the next. Again, this isn't to disagree with the socio-philosophical barriers, just to say that having advances be possible doesn't mean that they would be a rational use of resources for the individual even without that mindset. I could be way off of course, this isn't my main field. But I just can't shake the idea that with all the barriers mentioned in these texts that the lack of advances in these areas might make perfect rational sense.