Not trying to undermine your point, but I believe it won't take much long to re-train those "imported" doctors. Only those who are ambitious and bright would come to the US and I have at least a handful of friends from the medical school in Myanmar, who were in the same class year as I was, already doing their residencies. Most of them took ~2-3 years of taking the USMLE and applying for hospitals in the US which sponsors H1B (mostly the rural ones). They seem to be liking what opportunity they've been given to as far as I can tell. I actually regret quitting med school there and leaving for college in the US after my 2nd year just because I want to be an aerospace engineer (turns out, I cannot because there's almost no company that would hire an H1B aerospace engineer, so I had to change my studies back to comp sci).