That's why it's so concerning when you have people who confidently say they're great engineers who are experts in firmware, UIs, operating systems, and networking, yet when you ask them to write a 3sum or remove from a binary tree they freeze up and blame it on an unfair interview structure.
I'm a bit reminded of a chef who claims he can cook pasta, sushi, and pastries, yet when asked to fry an egg says that it's not fair to expect him to do so on the spot. A chef who can't cook when needed is about as useful as an engineer who can't code when needed.
There's a common double standard here though - when I've asked backend-type devs to do a UI sample/question (these are often "full stack" roles), the leet code geniuses dismiss my concerns as that not mattering if they flop it.
Naturally it's a "low bar" but it's an awfully low bar for a job that isn't entry level.