What is a medical device? Are we talking about things like thermometers, wheelchairs, and surgical knives. Is this saying you need a double-blind study for every new design of wheelchair?
https://www.fda.gov/MedicalDevices/DeviceRegulationandGuidan...
Sometimes the medical device is software. In fact, there are many software products on the markets whose makers don't even realize are unapproved medical devices. However, the FDA just doesn't have the manpower to investigate that on a wide scale.