It isn't because of that alone. In PH and Korea, senior doctors are expected to oversee junior or trainee doctors. These senior doctors are already overloaded with both giving care and training junior doctors.
Adding more MDs won't change anything because the residency/training bottleneck still exists and there is no way to change that.
This is why my SO left Vietnam for the US - getting paid $1-2k a year to train 6 juniors and work 60 hour shifts providing care is hellish.
The same is happening in Korea as well, with senior doctors leaving for Japan and the US now.