In this example, we're talking about an L6/staff role. If the role is correctly staffed, nobody should have to be looking over that person's shoulder questioni

In this example, we're talking about an L6/staff role. If the role is correctly staffed, nobody should have to be looking over that person's shoulder questioning data structure choices and algorithm efficiency regardless of what the person's background is. It's absolutely the case that there are people with 9 years of experience who are not prepared to meet the needs of that role. There are people with 19 and 29 and 49 years of experience that fit into that bucket. Practice alone doesn't get you there. But as you note, as a rule, you expect your bright, leetcode-grinding "newbie" to need mentoring and oversight to compensate for their propensity to rely on shallow theory where they don't know better from experience. That's not someone a team wants in a L6/staff role either! For high level roles, you need bright, curious people who are experienced but not rigid. Admittedly, there's only so many of them, but when you start having to fill those roles with people that don't meet each of those criteria, you can't be surprised when the team's morale and output suffer. Which is exactly what we see as an outcome of the recent boom (and each prior one), because you end up having the blind lead the blind through the minefield of engineering.. and that's going to be messy no matter how clever or book-studied those folk happen to be.