> This is a strange take. Why or how would you ever see someone do it? It is very unlikely you would be aware of them.
You would see someone be proficient at math or physics and then get surprised they had no degree, just like anything else. You can find such programmers everywhere, even algorithms are very easy to self study compared to math and physics, but people proficient in math or physics without a corresponding degree is almost non existent.
> Maybe it’s just going through a specific set of rote calculations and lab work needed.
I think the biggest problem is error correction. Everyone who learns math and physics accumulates errors as they learn, and if nobody is there to correct the wrong assumptions they will just continue to accumulate. To do that you need an instructor grading your tests, or at least almost everyone needs that since they can't grade their own answers fairly, their incorrect understanding leads to incorrect grading of their own answers.
This is why programming and algorithms is so easy to learn in comparison, since there its easy to grade yourself. If the program works you did it right, otherwise not. For algorithms there are plenty of sites you can practice implementing algorithms for problems and they tell you if you did it right. There are no such sites for math or physics, so there unless you are a genius at self correcting you need an instructor to just get proficient.
Edit: In short, if you can write code that works the first time you run it without testing etc, and you can do that over and over and never be wrong, then you can self learn math and physics without an instructor.
But if you need to execute your code and test to get it right, then you need an instructor to learn math and physics correctly as well.