No one is dodging the proper tax rate. Doctors were paying the rate specified in the tax code, just as you do.  There is very little savings a group of doctors can find in a partnership that they can't also find without a partnership, and a bit more accounting work. Doctor can easily share office space, office staff, equipment, etc., while still having separate corporations, this is the most commons scenario.
As I said , expect to see many partnerships dissolved, as doctors find other ways to work in groups, while maintaining the small business deduction. Many partnerships are already working on this.