Indeed, and I think we can also make better use of the "lesser" medical degrees as well. For instance I get most of my primary care from a nurse-practitioner or physicians-assistant. My parents' most beloved primary care "doctor," who is an absolute superstar, is a nurse-practitioner.

Maybe there could be some kind of a continuous work-and-training ladder, where you start as a NP, and move your way up as you get more training and practice. Or you can stop whenever you think you've reached your desired level.