“Physically, there was nothing that actually stopped the invention of such games centuries or even millennia earlier. It required no special level of science, skill, or materials. So why did it take so long? Rather than there being any constraints, soft or otherwise, I think it’s simply because innovation in general is so extremely rare. It’s a matter of absence, rather than of barriers. The reason we have had so many low-hanging fruit throughout history is just because very few people ever bother to think of how to do things differently. We are, most of us, quite set in our ways. So even today, when there are many more inventors alive than at any previous point in human history, the fermenting fruit still abound.