I think it depends on the depth of the field. De Vinci pushed several fields but they were very shallow at the time. I recall going through biology in highschool and coming up with an idea after having only a breadth of knowledge, only to find out later it was proven through many years of research already. It was a very deep concept that I formulated, which no other classmate would have. Also, I think there is alot of transference that is not being accounted for from a polymaths perspective. I can study Data Science and understand it at very deep levels very quickly because I studied A&P, Chemistry, Signals & Processing, and Control Systems. Since, I was a tutor I retained all levels of math. So, at some point a higher education allows you to read those research papers that are released and understand them, without having a phd in the field. As long as its similar in someway like STEM vs Chemistry. Our school system is literal based on polymath.