Yeah, I would say a much bigger issue than algorithm questions in interviews are interviewers who assume all programmers follow a particular path (usually the one they followed) and discriminate against those-that-did-not-follow-particular-path.
Computer science is a massive field that people enter through many different and unique ways. If you're trying to gatekeep and force everyone to enter through the same gate that you entered, you should not be an interviewer.
3D graphics is not a good moat, I agree.
There are much better moats -- such as recursion, there's no way I'd let someone in my team if the don't get recursion, even though we almost never use it :)
Computer science is a massive field that people enter through many different and unique ways. If you're trying to gatekeep and force everyone to enter through the same gate that you entered, you should not be an interviewer.