I might start somewhere around here: I think the fact that modern software is "terrible" is actually a sign of the dramatic success, not failure, of programming.
The reasons that Blow et all normally cite as why software is terrible are usually that, 20 and 30 years ago, engineers were able to pull off superhuman feats compared to the engineers of today. I accept this unquestionably. They wrote software that ran quicker and was more space-efficient than modern software. But running software that fit in kilobytes of RAM was never the goal of software engineering. The goal was providing value to your users.
Blow et. al. seem to think that efficient software is the goal. I couldn't disagree more. The goal is always to produce things that users can actually use. And if that means doing hideously inefficient things, like running your app inside a chrome shell, so be it, if that means you delivered value faster.
And the amount of engineering effort per unit of value created has gone down so much today compared to 30 years ago.
In the past, engineers could squander days or weeks trying to make code more memory efficient, or finding the exact right sequence of ASM instructions to waste less CPU cycles. These are issues I don't even have to think about. Heck, I can do extremely stupid and inefficient things, like use a garbage collector, or electron, and for the most part, users don't even care[1]. What an incredible success!
Essentially, I think what Blow is seeing when he cites the demise of modern software engineering is in fact that the bar to writing usable software has dropped immensely. I can understand why this is a frustrating thing for him, because it effectively means that his skillset is not as valuable as it used to be. But I just can't agree at all. How amazing that we can be so wasteful and yet still produce such great software, and furthermore what an incredible success that engineers like me don't need to even think about ASM and RAM efficiency.
[1] Yes, some users do care, and I think that a disproportionate majority of them hang out on Hacker News. :P