Nevertheless, it's an empirical question as to whether this method of recruiting produces the employees that maximize long-term profits for the company.
I don't doubt that a major reason for asking these types of questions, as opposed to an IQ test or something, is that it is basically illegal in the US to do so.
It's an empirical question about every method of recruiting. Making a bad hire can cost a company dearly. If there was some obviously better way of doing it, wouldn't companies do that?
Avoiding expensive lawsuits is likely another reason for leetcode gates.
I don't doubt that a major reason for asking these types of questions, as opposed to an IQ test or something, is that it is basically illegal in the US to do so.