>Understanding the full history of software isn't required to understand the difference between good or bad software.

No. We cannot talk about software in the same way we talk about other phenomena - it is obvious that various sciences have their different objects (e.g physics is the study of the physical world, biology the study of life etc.) - the point Marx was making is that economics (or rather, political economy) is a science which has an object strikingly similar to the science of history or the science of biology - it is a study in which one must engage the emergence and passing away of various forms of society, and of course to make any predictions or analyze trends. When detached from this view, the science that's left has no explanatory power. Why are wages the value that they are? Why does value appear as the objectification of labour? Why is it that the majority of large-scale productive capacity is owned by few? What can change given these parameters already determined? What can't change?

Marx was a great admirer of Darwin and they corresponded on at least one occasion. Like Darwin, Marx viewed man as a necessarily historical being: "The anatomy of man is a key to the anatomy of the ape. On the other hand, indications of higher forms in the lower species of animals can only be understood when the higher forms themselves are already known.", and similarly, "While focusing on political economy, Marx took the opportunity to criticize Hegel’s phenomenology. Specifically, he attacks its idealist premises that take the real starting point as the product of the thinking mind rather than as having an existence «outside the mind and independent of it»"[1] Marx is not only attacking Bastiat for his method, he's attacking it for the fact it is completely unscientific, unlike (he claims) his own[2].

But even granting your point, I'm highly skeptical one would find a software engineer who outright denies the value of history for software development, for instance to know what's been tried before and to know where things can go.

Marx's argument would say that the necessary and experienced development of things the way they are today is due to the premises already set in motion. If Bastiat claims that he has discovered universal human truths, this is to some extent a historical, social and empirical claim. You can't abstract away from that and still maintain the relevance of your theory to real world phenomena. To take this further, Marx's fuller critique was that economists were obsessed with appearance and in being ignorant of economic activity resulting from people acting in their interest (again, these interests transmitted from the past[0]) they miss the "whole picture" as you say.

[0] "Men make their own history, but they do not make it as they please; they do not make it under self-selected circumstances, but under circumstances existing already, given and transmitted from the past. The tradition of all dead generations weighs like a nightmare on the brains of the living. And just as they seem to be occupied with revolutionizing themselves and things, creating something that did not exist before,[...]" (Marx, The Eighteenth Brumaire of Louis Bonaparte, 1852)

[1] http://www.consecutio.org/2018/11/every-beginning-is-difficu...

[2] "Nevertheless, the human mind has for more than 2,000 years sought in vain to get to the bottom of it all, whilst on the other hand, to the successful analysis of much more composite and complex forms, there has been at least an approximation. Why? Because the body, as an organic whole, is more easy of study than are the cells of that body. In the analysis of economic forms, moreover, neither microscopes nor chemical reagents are of use. The force of abstraction must replace both."