Final answer:
American beliefs and values, economic interests, social disparities, and the level of care and innovation in the U.S. health care system are factors that have protected it from a major overhaul.
Step-by-step explanation:
The factors that have primarily shielded the U.S. health care system from a major overhaul include a combination of beliefs and values, economic factors, social factors, and science and technology. American values such as individualism and the preference for private enterprise over government involvement have influenced resistance to systemic changes. Economically, the significant costs associated with the current health care system and the vested interests of insurance companies and other stakeholders often resist change to maintain profitability. Socially, disparities in healthcare availability and quality affect historically disadvantaged racial groups, ethnicities, socio-economic statuses, and genders differently, which complicates the push for a uniform overhaul. The high quality of care and innovation provided by the U.S. healthcare system also acts as a buffer against calls for change, despite the challenges in cost and access to basic medical care for all.