Exactly, that's one reason why government paid social health care is aligned with this: The government benefits from doing prevention programmes as it is cheaper than late treatment.

Germany had all kind of preventative help/medicine when I lived there.

Why would a private insurer not have the same incentive? Collect full premiums, but overall lower costs with early detection and treatment?

The older and sicker patients tend to move from the private insurer's risk pool to the public one.

Agreed. But there is still an incentive for private insurers to limit future costs.

The US system hopes that people get untreatable stage 4 cancer and die quickly.

Maybe the insurers. Hospitals prefer treating them in the most expensive way.

Heard the Chair of the Department of Medicine at UCSF say they make most of their money on elective procedures.