I literally don't know how compilers work. I've written code for apps that are still in production 10 years later.

Are you working on compilers? If not it seems you did not understand what is being talked about here.

Do you lack fundamental understand of those apps you built that are still in use? Did you lack understanding of their workings when you built them?

You don’t need to understand compilers because the code it compiles, when valid according to the language specification, is supposed to work as written, and virtually always does. There is no language specification and no “as written” with LLMs.

No problem with that.

However, at one point in my career, I was frustrated with limitations in a language (Fortran II) and my curiosity got the better of me and I studied compilers thoroughly.

This led to a new job and the understanding of many new useful programming concepts. Very rewarding.

But if you are curious, studying compilers, maybe even writing a new one, will give you tools to do other things.

While working with LLMs, much of my experience gives me new ideas to push the LLM to explore.

Have you written a compiler, though?