Like others, I agree with parts of what you are saying and disagree with others.
All graduating DPMs do not automatically deserve the best PG training. It is a privilege and a job which is applied for - not something which is guaranteed to all. If the number of graduates outnumber the number of residency programs which get the rearfoot case numbers to be a PMS-36, then the less desirable applicants will have to settle for less popular residencies (and/or be very flexible about location).
The competition for top residencies is what makes students "work harder and strive for higher goals." If everyone knew they were getting a similar PMS-36, there would be little competition (except for maybe those programs with a big name director or prime location). If you back up not too far in podiatry's history, top graduates were happy just to be offered any residency. Times have changed, but I feel that the best programs should remain that way today: competed for by the most highly qualified and competent graduates. Again, a good PMS-36 should be strived for, not expected.
As for the "not everyone is a foot and ankle surgeon" portion, I believe that is because there is only a limited demand for those services. Not every pod resident has the dexterity to be a good surgeon, and others may lack the knowledge to grasp the literature or work ethic to take call and meet surgeon demands. Not every neurologist is a neurosurgeon, not every dentist is an oral surgeon, not every cardiologist is an interventional cardiologist, etc. Sometimes only the best, brightest, and most capable graduates get a crack at the top training programs. For DPM residencies, there are just not enough level-1 trauma centers to support all current DPM residencies truly providing RF numbers (without having residents double-scrub, count assists as primary surgeon cases, etc), and there is really no need to having every pod graduate learn the complex RF cases if they're not all going to be doing them in their practice.
I think a scored part I NBPME board exam would be interesting for podiatry and the residency selection process. As it stands, all the residencies have to judge candidates by is GPA, but some schools use straight letter grades, some use +/-, and some use 70-100 grading. A numerical board exam score may be able to help to level the playing field for residency candidates and help residencies know what they are getting.