In the spirit of constructive discussion, I have several thoughts about why other people may not see this. One, it's quite possible this is a very locale specific phenomena.
Secondly, I have tended to work in - and therefore interview people for - very mainstream languages, I suspect the experience of someone who works in/interviews for Haskell would be very different.
Finally, it's entirely possible that most of the applicants are by definition, the ones who find it difficult to get and/or hold on to a job, and that throws out the experience of the recruiting process, and that means they make up a disproportionate number of applicants, despite being a minority of programmers in the workplace.
I have encountered them in teams that I’ve inherited, and although I don’t find that it’s the majority of applicants at interview it’s a significant proportion and you get no indication of it from other parts of the interview. I’m talking about people who struggle to work out that they need a loop.
Being able to talk about playing the piano is not the same as being able to play the piano.
My interview approach is simple - I talk to people about the things they’ve done and ask questions based on that. I discuss higher level concepts and don’t worry about syntax. I take about one hour, sometimes a little longer. I have never hired or recommended a hire of a dud.
80% of the people in this industry write CRUD apps, web apps at that, or simple API backends for said apps. Some of course create new languages and kernels, and I don’t know what an interview process needs to be for that skillset, but for 80% what I do is perfectly adequate.