"...a key is early and accurate diagnosis of patient's real illnesses. I think incremental costs of diagnosis will be paid for by lower cost of earlier treatment."
It is the diagnostic part (which prevents nothing) of "preventive care" that makes it so expensive.
The cost of locating one case of actual or incipient colon cancer earlier than it would otherwise be detected is well into seven figures by any estimate I am aware of. The earlier detection then leads to increased survival and a longer course of continuing treatment.
This is not to say that colonoscopies are bad or should be eliminated. It is just stating the obvious fact that earlier diagnosis (unlike true prevention) greatly increases total medical expenses.
The most effective way of treating one's teeth is simply to allow them to rot out of the head (if they will), perhaps paying a dollar or a fraction thereof to have teeth pulled as their condition becomes unbearable. This is not hypothetical: It is the "treatment" regimen in common use among the underclass in much of the "underdeveloped" world, where the extraction is done with a pair of pliers by a guy squatting on the street.
The unfortunate fact is that, if we want all the advanced diagnosis and early treatment that is available, it creates a very heavy additional component in the total cost of medical care.
The economic advantage of true preventive care, such as inoculation, is, of course, undeniable.