If we see US seniors choosing EM less, it won't be from fear of a difficult match, it'll be fear of what their jobs will look like after training, if they can find jobs at all.
Things to worry about: Higher patient per hour expectations, lower hourly wages, increasing presence of ER midlevels, and increasing numbers and sizes of residency programs (because from the hospital's perspective, trainees function like heavily discounted, highly productive midlevels). The number of residency slots that has been added in the last decade or so is absurd - something like 1000 seats per year - which is the cause of the predicted excess I mention above. And that expansion is not slowing down, because there is no governing body in place to block new programs or close recently started ones. The ACGME's job is to decide if a program meets criteria to produce adequately trained physicians, not control numbers to influence job markets.
We are nowhere near hitting a ceiling to this phenomenon because there are far more total applicants than spots, and endless hospitals that would love to add some $50k/yr physician extenders to their ED. In a typical market model, excess supply will lead to value drop and contraction to better match demand. But in our model, the programs determining supply do not suffer any repercussion for their graduates ending up with poor pay, bad locations, or unemployment. They get all the same value out of someone during their time in the residency, by efficiently seeing patients and generating notes for attendings to cosign. The only way this can "market correct" is for the spots to become so worthless that international applicants don't want them and they go completely unfilled. Based on how some of the least desirable programs in the lowest paid specialties still find bodies for their spots, I don't think that's happening until way past the point of no return for EM.
