Do you have actual stats for that? It’s very surprising to me. I feel that football (both american and european), rugby, ski, fighting sports, … would lead to a lot more injuries and at a younger age.
Of course hitting a stick in the ground at 90mph++ thousands of time is going to cause injuries. The increased number of mats for the amateurs is probably not helping. On the other side the fact that pro and amateurs are physically training more than they used to is almost certainly going to reduce the number of injuries. The remaining ones will be more specific to golf (wrist injuries) or bad training (knees/back for people running a lot like Tiger did).