Odds are, I have studied the topic of learning techniques to a much deeper degree than you are. I also studied veterinary medicine. Therefor I can say: Yes, surgeons will know most of what they know from reading books or consuming learning materials, not from practicing. Some surgeons might disagree, but this really is the case.

And you would want to be operated on by surgeons who are trained that way. Especially in Human medicine, "practice" is just too damn expensive. And routine surgical tasks just don't teach you all the shit that go wrong. Also, surgical procedures, especially when you consider all their variations or complications, have a long tail problem. Some things are just really rare.

There is a reason why surgeries are performed by doctors, and not by nurses. Doctors have so much knowledge and information in their head - most of it not acquired through practice, contrary to romantic belief, but rather through long hours over years of studying. We often need to "debug" a living organism. But we can't say "hm, let's run this again".