Countries that do that usually have med school programs that last longer than 4 years. US med schools would have to add in all the required classes from undergrad.

Then you have to take into account that you the US doesn’t have a national high school curriculum, so the first 2 years of undergrad are essentially just getting everyone in the same page.

You’d likely be looking at a 6-7 year program with a much higher failure rate. It’s not a clear cut win and it would take a huge amount of coordination and effort.