While it is important to know low level details if you are going to understand how the high level language is built, it is not necessarily important to know how the high level language works if such details don't readily aid you in your task.
It might be nice and it might be cool, but it doesn't matter so much. Or to put it another way, how many people learned how tracing JITs work to do JS form validation? Would it matter if I did/didn't know this? Would it make a better form validator? Eh.
There seems to be some limit to the benefit that knowing such LL details provides. It's icing, but it is most definitely not the cake, and when your time/budget/skills are limited, you want cake, not icing.
Who gives a shit? Computers are cheap, programmers are expensive. You're probably deploying onto Amazon anyways, so don't kid yourself.
In the vast majority of cases, it doesn't help your average coder one bit to know about whether or not a particular type of shift on their platform is arithmetic or logical, or how their cache is structured (again, running in a VM, lolzors).
There are cases where it matters--and surprise surprise, most of us don't work in those fields.
