... Nobody expects doctors to be perfect. Every profession has a standard of care that is established, not by lawyers, but by practitioners within that profession. Doctors, accountants, real estate brokers, contractors, and yes, lawyers too.
The difference with doctors though is that when they fall below the standard of care, the results are often catastrophic because they are dealing with human life and well-being. There is a lot of risk in practicing medicine but there is also a lot of reward in terms of financial compensation.
And to my point that doctors establish the standard of care, there has never been a medical malpractice trial where the plaintiff did not have as an expert witness a doctor who will testify that the defendant doctor's actions fell below the standard of care.
If a med mal case were so unethically brought as you claim, it would be extremely difficult to find an expert physician willing to testify that the defendant doctor's actions fell below the standard of care.
I will say it again, lawyers do not sign up med mal cases on a whim. Yes, there are outliers and lawyers who do that will learn an expensive lesson when their case goes south. Med mal cases are terribly expensive and labor intensive with a high likelihood of a defense verdict in most cases. Juries sympathize with doctors and it is very difficult to get a plaintiff's verdict in Med Mal cases.