I don't really think it's possible to know it all. There's no denying the wisdom and intellectual capabilities of these men, but knowledge has expanded and sgphifted so much since then it would have been a convoluted mess were it not for specialization.
Specialization exists everywhere- in nature and in education.
The same was group of body cells come together to achieve a tiny part of the full body functions is the same way the man of today can specialize and become a master in a field. Not all of them. I don't believe that.
I've always enjoyed your writing, I learn from it.