sorry if you are offended, history is what it is whether or not one likes it.
First, roughly 17% of family practice residencies go unfilled annually (AAFP). Second, that is an excellent reason to support clinical training budget increases in a time of primary care provider shortages.
I would suggest that you actually know a little about the history that you often cite before using them.
The acceptance of DOs by MDs in an interesting story but there is no parallel to the current DNP debate. From the time it was founded, osteopathic medicine in the US had similar curriculum to their MD counterparts - and as time changed and curriculum changed, so has both MD and DO curriculums. The battle for acceptance dealt with issues that are unrelated to current debate.
Second - the studies you cite (or refer to) and the conclusion you are reaching are two seperate issues. Most of the studies are underpowered or the goals of the study differ from the conclusion most people make - thereby making sweeping generalization unwarranted. Take a look at them with a critical eye (journal club style) and you would be fascinated by the results.
Third - public health, epidemiology, statistics and "journal club" are indeed integrated into medical school's curriculum.
Fourth - like it nor not, society has adopted "doctor" to mean physicians. People say "I'm going to the doctor". Nurses say "The doctor is going to see you". And in similar context, society has accepted dentist and chiropractors as "doctors" - although with chiropractors, there is huge public misconception that they are indeed physicians who trained in chiropractics (and it doesn't help that a few of them refer to themselves as chiropractic physicians). And if you are a purist at heart, look up the origin of the word "doctor" in Oxford's OED (the accepted authority on the evolution of words in the English langaguage). It's an interest read (and definately different than what a lot of people on SDN proclaim to be the origin of the word doctor)
And last - several NP students have posted their curriculum to show how rigorous it is. There have been several posts showing how lax some DNP's curriculums are. And there in lies the issue. How is a potential employer to know whether an NP applicant's curriculum was rigorous or full of non-clinical classes? Should all future NPs post a copy of their curriculum on their resume? What about direct DNP schools who take people with no healthcare experience and give them their BSN (or MSN) and DNP simultaneously. Should an employer really have to spend months (and years - depending on the skill level) to teach someone how to practice clinically (on-the-job training) while paying them a full salary (and taking full liability)? And why do some DNP schools call their clinical rotation "residency" instead of "rotations"? Are we going to confuse the meaning of that word too? Basically the point of this paragraph is to say that the curriculum should be standardized.