Many technical interviews are simply “a lie”
Think about Set Theory.
There is a set of people A that cannot do the job.
There is a set of people B that fits the Job.
There is a set of people C that fails in the interview
There is a set of people D that approves the interview.
The goal should be C should be almost equal to A
D should be almost equal to B
Then, as A intersection B is zero by definition, C intersection B should also be zero. And no one check that situation is true.
I think interviews are so strict that makes D equal to a very small subset of B.
Then, in my experience, I succeeded in interviews most answering questions I learned in other interviews but not things I learned at a job.
No company checks if people who failed in interviews have successful jobs in the same position in other companies.