1) Government regulations - healthcare is and has been an important political issue, and because of this there is a mountain of legislation that must be accounted for when operating in the field.
2) Healthcare bureaucracy - The interlocking relationships and ecosystem of healthcare from Patients to Doctors to Hospitals to Insurance Companies to Government is even difficult for insiders to navigate.
3) Fear of liability/litigation - Healthcare is a scary place for "bleeding" edge technology, and few institutions are willing to be operating there.
The fact is most normal ppl don't care about their health until they get a heart attack.