Maybe it should be that way, however in practice it doesn't work. The ACA specifically requires free preventive services because research has shown that when patients have to pay they often skip it. And when they skip preventive care that causes the spread of infectious diseases, and allows small problems to turn into serious problems that are more difficult and expensive to treat. So this is important from a public health standpoint regardless of concerns over economic efficiency or personal responsibility.

https://www.healthcare.gov/coverage/preventive-care-benefits...