All of the interviews I've done over the past few years have used leetcode, or some variant, but most of them used it only as one dimension when considering candidates. If someone was leet at coding, but bad at team work, they didn't have a chance. The opposite position was far more favorable (I've heard "you can train people to have skills, so hire for the things you can't teach" more often than once). In fact, I'm seeing companies swing the pendulum a little too far away from skills, but that's to be expected, when doing this kind of balancing.
Granted, this is most likely not where most HNers would not like to spend their work day, but it does have its own perks.
I'm not sure how you test the first three qualities reliably in an interview. The point of leetcode interviews is that they are arguably harder to game: if you manage to write some code solving some problem, you at least memorized a solution and somewhat understood it.
Maybe you trust engineers to be completely transparent, but then you also let in a different kind of "brilliant jerk" (as you put it) who learnt to fake interest.
Or got someone else to do it for you.
I think you underestimate the skill of interviewers. You can learn a lot about a person from one directed conversation, if you want to.
I assume you're talking about cheating? That's mostly possible for remote interviews, not that easy to pull off.
> I think you underestimate the skill of interviewers. You can learn a lot about a person from one directed conversation, if you want to.
You can definitely learn a lot, but the three qualities you mentioned were:
> interested in the work, willing to learn, and aren't a jerk
If someone wants the job because of $REASONS that differ from these, they can still practice to show these traits during the interview.
You could dig deeper in their portfolio if they have one, but my point is that the 1h interview is not going to bring you much more with respect to these three criteria you mentioned.
Many can, but over time that practice itself becomes evident to a good interviewer.
No process is perfect, nor can it be. But, that a few can slip through doesn't mean that all can, or do.