In regard to what has changed most in the last near half century some would answer medical advances, mainly in diagnostic techniques and therapeutics.For someone who has seen those happen they are incredible and marvelous but that is not what has changed the relationship between physician and patient. In the sixties, physicians used the tools of the day to diagnose and treat patient, so do they today even as the tools are much better and more varied. No relationship change there.
I submit that three factors acting alone and interacting with the other two have brought about a sea change. The factors are: 1) loss of physician autonomy, 2) a change in medical ethics (even the name has changed to professionalism) and 3) method of payment for physician services. I argue that the third has been a major factor in loss of autonomy and has triggered the ethical changes.