Assuming your timeline and metallurgical claims to be true, you're conflating engineering and (materials) science.

Humans have been using steel for however long, when and where it was understood to be an appropriate solution to a problem. In some sense, engineering is the development and application of that understanding. You do not need to have a molecular explanation of the interaction between carbon and iron to do effective engineering[-1] with steel.[0] Science seeks to explain how and why things are the way they are, and this can inform engineering, but it is not prerequisite.

I think that machine learning as a field has more of an understanding of how LLMs work than your parent post makes out. But I agree with the thrust of that comment because it's obvious that the reckless startups that are pushing LLMs as a solution to everything are not doing effective engineering.

[-1] "effective engineering" -- that's getting results, yes, but only with reasonable efficiency and always with safety being a fundamental consideration throughout

[0] No, I'm not saying that every instance of the use of steel has been effective/efficient/safe.