not saying that you are incorrect, but "basic" is relative.
To understand Linux networking should we also understand basic linux kernel ? or basic chemistry to understand what happens inside the cpu ?
We should all stand on the (stable) shoulders of giants. I would call that good (also relative indeed) documentation that abstract us from the level below/above.
Even if there is an abstraction layer with nice boundaries and well documented, you can still not ignore the layer below and pretend its raining.
When you are making a web app (for advertising purposes since this is HN), can you ignore understanding HTTP and TCP and IP? Would you hire a web-application developer who didnt know how to setup a web-server or load-balance his app?
My company does this all the time.
In fact, in the absence of our step-by-step guides, I would estimate that maybe 5% of the development team could successfully configure their local web server on their own.
I don’t use most of the fundamentals I learned in school directly on a daily basis, but I do use them almost every day to inform the decisions I make about higher level things.