To try to get back on track here:
Although I have nothing against IMG's at all, the US is likely going to need to limit the number of IMG's getting residency spots and prioritize spots to US grads. The system is coming to the breaking point. However, I don't think we'll get to a two stage match -- 1) PD's will hate it, 2) It would delay IMG appointments even later which would cause more visa problems, and 3) it would not affect programs who take candidates outside the match, and because of #2 might actually encourage programs to take more residents outside the match. So, unless the match becomes "all in" = everyone must use it, then I don't see this as a solution.
I think there was almost a poor "US grad match" as about 1,700 US seniors and past graduates of US schools went unmatched this round. I think that if the son or daughter of a "big whig" doens't match, they will be focused on applying more broadly in the next match, and won't try to limit H visas as this would take too long. I seriously doubt that the Obama administration would want to limit H visas to decrease competition for US grads, partly as Obama is part Kenyan and appears to be pro-immigrant.
While US medical schools may believe that the students they are producing are a "better product", there are literally thousands of IMGs/FMGs that have a better application, higher board scores and clinical evals, than perhaps the bottom 10 to 25% of US schools.
Also, many residency PDs are foreign grads themselves, and if not, then have taken foreign grads into their programs for years. One such community IM program I have seen takes almost ALL, i.e. 95% of their residents from India, and many of their attendings are foreign trained, there is no incentive for the PD to favor US grads over IMGs/FMGs. A person at a US school would have to call them and say "Uh, a lot of our students didn't match last year, how do you think they are stacking up when they apply to your program?" Also, many US grads wouldn't apply to many of the places that FMGs/IMGs train, which is why many don't participate in the match, as they are run-down compared to academic medical centers affiliated with US schools, and they are in poor locations. Would a US student want to go to residency in Harlem or the Bronx?? Such locations have many FMGs/IMGs . . .
The only way to "force" residency programs to take US grads is to make a law, like restricting the H visa, which will not be passed under the current administration. At any rate "forcing" residency programs to take US students won't be possible as PDs feel they have the right to decide who is best for their program, the best that would happen is that some residency programs over the next 10 years might have a higher and higher percentage of US grads, but certainly not enough to accomodate the huge increases in the AMG population.
Nobody has to do anything. Sure US medical school administrators might say that we "have to do something" to give US med school students jobs. But nobody cares besides the AMGs left out and the US med schools, and considering how heterogeneous the residency programs are in the US, the problem won't get "fixed". There will always be FMGs/IMGs by the thousands applying to and matching in residency, totally displacing them would take decades and a change in culture. Maybe 100% acacemic centers can be made to take all US students no matter how bad they are, but many community programs won't. There will always be places that US grads don't want to go for residency training . . .
The biggest problem is that the residency positions that will be "fought over" are in primary care fields like IM, Peds, Family . . . the percentage of US students wanting these fields will have to change, and more US students aiming for pretigious IM residencies will have to settle for IM in podunk country. The strain in terms of enough derm, etc . . . residencies is being felt. Even amoung residencies like surgery, IMGs/FMGs are filling these by the boat load, as there are many FMG run surgery programs. So the "poor match" for US grads has already happened for hundreds of US med students who wanted surgery or radiology, couldn't get it, while many US IMGs and FMGs did . . . there wasn't an outcry when this happened and it will happen for IM and Peds too.
While many law school grads can't find a job after graduation, or can't find the right or good job, if the same thing happens to a small but significant percentage of US students, say 10% don't match each year, there won't be any tears shed by many outside of US medical schools and this won't be seen as a "problem" by Congress or anyone outside of medicine and will just be considered a reality and a consequence of US schools ramping up enrollment numbers to make money a sort of "administrators at US schools got what they deserved" as this is trying to form a monopoly on residency positions in the US, which has had a long history of being a meritocracy as FMGs/IMGs do get orthopaedic surgery positions even . . . The price of getting significant monopoloy on all the residency positions in the US for AMGs will be that maybe 10% of US med schools classes don't match. Remember that thousands of perhaps qualified IMGs/FMGs don't match while the best of them do, there is a HUGE pool of FMG/IMGs to compete against.
In the end if there is "poor US grad match" in the future it is the fault of the US med schools that ramped up enrollment in the name of greed and wanted to create a monopoly on residency positions, and they are the ones to blame. It will be impossible for US grads to simply displace FMGs/IMGs at many program as there is no incentive for PDs to do this, many of whom are FMGs/IMGs.