the less experienced a practitioner of any given art, the more likely they are to look for the rare and unusual explanations *first*.That seems obvious. Why are inexperienced practitioners more likely to look for unusual explanations? Because they don't know yet what the usual explanations are, of course.
It seems to me that one of the most important forms of experience that people get is to learn which problems are common and which ones are rare. Sometimes beginners come to me with broken programs and ask what the problem is and I find it instantly. But when they ask me how they could have found the same problem themselves without asking for help, I don't have very good advice: I looked for that problem because I knew it was a common problem, and I knew it was a common problem because I had made the same mistake six times myself.
I agree with your observation that beginners often look in the wrong places. But I don't think that advising them to look in the right places is very helpful. If they knew what the right place was, they wouldn't be beginners.