I don't think LLMs were ever meant to completely replace human engineering, at least in the way we think of engineering as a craft. But the truth is the world is changing, and with LLMs/AI, the goalposts are changing, too. With massive economies of scale and huge output, the goal is less and less good engineering and more and more pure output.
Put it another way, the post-AI world considers a reduction of quality to be an acceptable tradeoff for the massive short-term gains. Moreover, although quantity over quality is not exactly a new concept, what AI does is magnify and distill that concept as a prime directive.
Code doesn't have to work well to be profitable given how cheaply in can be produced, and that's a general effect of technology that can reach global audiences, and AI is the apex of that technology.
I don't think there is a nuanced view: AI is an all-around bad thing and its positives in the short-term will be vastly dwarfed by its negatives except for those who have become specialized at concentrating wealth at the expense of the common good.