The harsh truth is that very few fields are actually “DO friendly” more like DO tolerant. The reality is that most program in most fields would rather fill with all US MDs, but that just isn’t realistic because there are thousands more slots than US MD graduates. This is seen quite plainly in how when a specialty has less US MD applicants, lo and behold it suddenly becomes more “DO friendly.” It’s also why fields like plastic surgery, who have more elite US MDs applying than spots, have extremely few DOs and some years none.
This is what is happening with fields like anesthesia and radiology, and why you see hoards of DOs matching into EM. The phenomena is exacerbated even further by the ever continuing expansion of medical schools (MD and DO, but even moreso for DO) that inherently increases the applicant to spot ratio across the board.
Specialties wax and wane in competitiveness, it can be hard to predict exactly what will happen a few years down the road.
Except for EM. That runaway train is fully off the rails and is actively in a complete specialty meltdown and it isn’t going to get any better for a LONG time, if ever.