"... For 95% of these Canadian MD's it will be impossible to immigrate into US. Canadian standards are lower, exams and licensing has changed. States all require USMLE, US Residency and US Board exams which are not equivalent to Canadian exams. US Green Cards/H1B/ citizenship can take years to acquire. On top of that the US has an oversupply of physicians...."

You simply do not know what you are talking about.

A physician would come into the USA under something like an EA-1 "exceptional talent" - easy to get for anyone with a PHD, like an MD. The USA doesn't have points systems so a good attorney can craft a story, and things like age do not come into play. The Homeland Security/INS process now states that an applicant cannot stay in a status for more than 6 moths from date of filing the application. From EA-1 to permanent residency = 6 months. Tops

That is just one path.