Huh? If you are an insurance company and it costs $20 to prevent something compared to the $10K to fix it then there is definitely an incentive for prevntative care. I see the opposite, with socialized medicine there is no incentive to improve.
Insurance companies make money by a)investing premiums and b) by denying whatever they can c)paying as little as they can d)charging as much as they can.
As far as it being a no brainer to spend $20 to prevent something that will cost $10K to fix: look at birth control coverage in the US under Obama care and what is being proposed/slashed.
The reason that NO INSURER cried out against no charges for birth control is because birth control is relatively inexpensive compared with covering prenatal and child birth care. However, if the can call pregnancies preexisting conditions (which they used to do all the time. Happened to me when the doc insisted my due date was a month earlier than it was so we were on the hook for all costs related to our oldest child's birth, prenatal, labor/deliver, etc. And that was extremely common in those days).
Look at what's happening now re: birth control.
I've said before that the only reason I was worried/opposed to single payer is that many/most hospitals/clinics/providers are struggling with the fact that Medicare reimbursements do not actually cover the cost of providing care. That's long been true of Medicaid, which is why when possible many providers limit the number of medicaid patients they will see. Now, providers are looking to see what they can do re: medicare patients. It seems inevitable that the same struggles will come up with a single payer system.
The other issue is like what is currently happening in the war over coverage for birth control, pregnancy, pre-existing conditions. I don't want a single entity driven by rabid politicians making medical decisions for me or for anyone else.