Some remarks:
The AMA does not have a monopoly. The AMA is a relatively weak organization that only a minority of physicians are members of.
30% of healthcare is spent on the last several months of life. Healthcare should be rationed, and as a society we have to reach a decision that extending someone's life for several months in someone with terminal cancer or other serious illness is just not worth it. For example, it's not uncommon for someone with terminal cancer to spend months in the intensive care unit getting fed through a tube, having their blood work checked daily, being on a ventilator, getting expensive imaging tests, and consuming a large amount of human resources in terms of physicians, nurses, and other healthcare staff. As a physician I have seen people consume far more healthcare dollars in the last few days (and even hours) of their life than has been spent on me in my 29 years of life.
30% of healthcare spending is overhead, and many insurance companies make billions in profit per year. The highest paid executive made over 100 million dollars recently. Insurance does not actually contribute to the care of a patient, nor does it make it more efficient. Spending on this overhead should be drastically streamlined.
Physicians spend an incredible amount of time for comprehensive medical training, only to rely on specialists, physical therapists, dieticians, pharmacists, and other peripheral healthcare providers. Either we need to reduce the number of these healthcare providers, or we need to narrow the scope of physician education and shorten the length of training.
Americans have horrific health habits. The prevalence of obesity, diabetes, heart disease, smoking, and lack of exercise makes for an extremity expensive population. Obesity increases risks of countless other diseases, and increases the complication rate for virtually every surgery or hospital stay, which increases length of hospital stay and requires more costly procedures/tests. We as a country need to be more serious about physical fitness.
Finally, Americans need to shift their mentality away from healthcare being a buffet. What happens in a buffet is that people fill their plates, engorge themselves, and go home feeling sick. If we were faced with the cost of healthcare for each procedure or each service provided, we would stop wanting unnecessary MRI scans, unnecessary home nursing for minor dressing changes, unnecessary physical therapists because the patients are too lazy to get out of bed once in a while, etc. I'm not saying that home nursing, MRI scans, or physical therapists are unnecessary; but that they are currently being grossly over-utilized, mostly because we all think that someone else is paying the bill. If people paid for their own hospital stay, they would not want to stay in the hospital an extra day just because it's not convenient for their family members to pick them up, they would not need to pay people to get out of bed, and they would not need people to put a bandage on themselves.