An Oversupply Destory The Society

I have no time to follow the medical insurance issue in U.S(Many Japanese show much interests with this too.)I only heard that medical cost is incredibly expensive in U.S because the medical profession is  oversupplied.
An insurance depends on the invisible social reliance.But this oversupply seems to damage fundamental elements of social reliance. Modern society has no way to resolve this problem yet.Economics may be useless.A doctor is too clever to compete with low price each other.An oversupply of profession is essentially exception of market balance.Market can't reduce the amount of the medical profession.An oversupply does more harm than good.