Gaawd I'm so tired of this discussion. Of course coding interviews measure coding skills, if you can't code you can't complete the interview. Are other factors also present? Sure! But no amount of zen will help you if you can't program.

Okay maybe a tiny minority of people are simultaneously great programmers and also incapable of proving it by solving some simpleish tasks. But I'd wager that's a very small minority.

Most people who actually know programming will breeze through the interview questions I've encountered, they won't complain that this isn't representative of their job because it is - programming is their job, and completing a simple well defined task is the best case for the job. Normally it's less defined, less simple, and much bigger. Oh but it's not the exact type of task i normally do well then brother you don't really know programming. You just know a tiny niche of exactly the specific thing you normally do, you don't actually know the language. You're likely not a very good developer and exactly the kind of person these interviews are supposed to weed out.