Amazon’s recent announcement of its deal to buy One Medical for $3.9 billion generated a wave of speculation on how the tech giant might transform primary care in the United States. Will it build a health care system that is as easy to access as Amazon’s website — one that offers products and services at the click of the button? Maybe it could employ artificial intelligence that can combine a wide array of individual patients’ data to help them identify and regularly receive the services, medicines, foods, and other supplies they need to recover from an illness or to stay healthy. Or use smart devices that would nudge people to take their medications or exercise.