While I understand the sentiment, the things you learn in PA school and medical school are very different. PA school seems like it is focused on rapidly acquiring some very basic medical knowledge and applying it to the job of being a PA, whereas medical school is focused on an in-depth understanding of physiology and pathophysiology with arguably less practical application. I rotated with some PA students on one service once, and while they could present patients and write notes, they just didn't have the same understanding of disease processes that we did. That's not a putdown: they were very intelligent quick learners, but the focus of their education was just very different.
A PA needs to come out of school ready to see patients and function in a relatively autonomous role, whereas a medical student should come out of school fairly undifferentiated, but with a much larger and broader base of knowledge.