They won't. Just as most modern devs can't edit assembly and would take days to write a bare bone network communcation, they won't need to learn certain things we did. And they will excell in other skills, making some old aged senior devs obsolete.
A senior that uses modern dev tool chains will allways have a huge edge. That has allways been true. But that senior relying only on their hard earned knowledge will become the kind of dinosaurs we knew when we started.
Yea they can't edit assembly because they have reliable tools that work 100% of the time, always. They don't have to manually inspect the output of the assembler every time they write any code. This is not even close to the same thing as LLMs.