Uro,
I think your understanding of the situation is accurate. But you've only touched upon probably 50% of what goes on. If your'e main goal is to become an EM doctor, then you would be fine going the DO or MD route as long as either is okay by you.
The AOA and ACGME governing bodies for EM residency programs have an unbelievable amount of stipulation and reinforcement in play as to the quality of resident education. This in and of itself will probably gaurantee that you'd be an excellent EM physician as long as you are motivated and have a good grasp of the basics. Remember, of the practicing EM physicians in the USA, over 20% are DOs. The number is growing.
Every year there are unfilled spots in the AOA match. The reasoning is obvious and you have already stated it in your previous comments. Many DO candidates apply to only ACGME spots due to quality of residency issues. Fortunately, many DOs make it into these allopathic spots. I'm sure there is resentment on the part of allopathic medical students who don't match, but what it comes down to is the quality of the applicant, not the title you have. And by the way, most of these DO EM programs fill in the scramble later on.
Most EM DO residencies are base out of community type hosptials. As such, there is no funding from a large university hospital, no state funding, no paid faculty, no major research, no extra perks. Many of these programs require their residents to rotate at Trauma centers in another city. These trauma centers are usually already claimed by another allopathic residency program. Fortunately, many of these off service rotations only last a few months 2-4 at most.
It's obvious then, that most candidates will try to match into a program that provides the best education possible. With that said, it is likely to be the best funded programs. Money talks. Allopathic programs have money for the above stated reasons.
There is much more to consider. Many DOs are quite happy with their ostepathic EM programs. The good trade offs that stand out in my mind w/ DO residencies vs the later is more quality time with faculty, better and more cohesive working environments, more time for investment in the individual. This may not be unique to just osteopathic programs however. Almost seems like a small college vs a large university decision. Thats the way I percieve it in my mind anyway.
If you look closely, you'll see a select few DO EM programs that always fill. These are generally the well established programs. For example, the program I'm at Lehigh Valley in PA has our own Trauma Center. We had the most trauma visits in PA last year. Furthermore, we have paid faculty fully invested in resident education. Although we are technically a community program, the funding behind the hospital allows for an awesome program without the negatives of an academic institution. We have allopathic residents rotating at our hospital, which is ironic. Anyways, not all programs are 100% alike.