Ok but the question is why are some of these questions even considered the 'base' level of knowledge for interviews? At least on the front end side we still ask about these algorithms even though binary search trees and Djikstra's have almost no application in our work.

The reason for these questions being considered 'fundamental' seems totally contrived, and that's that everyone studied them in their CS program, not necessarily because that's the kind of knowledge you apply day to day.