I don't disagree with you and I agree with your take on understanding data structures and algorithms ... it is important, but making 80 to 90 percent of your recruitment process based on this and on playing games with quizzes and LeetCode is idiotic. There are lots of other factors that play a vitally important role in creating great software and most big companies do NOTHING to pay attention to these factors albeit I fully admit to this being hard to test for. That's why I offer every company I'm recruited into to do a paid (or free albeit open source) work sample test if they want to do so. Most don't take me up on this offer and I think its idiotic but it is what it is.