Indeed, but the point is that with BI, they would be on the hook for those excess costs. Preventative medicine is cheaper and when the excess cost of an ER visit comes directly out of patients' pockets, they will be more diligent about prevention.
Good analogy is car maintenance. Most people are very diligent about oil changes because they (inherently, I would argue) recognize the cost structure.
A lot of people aren't very diligent. It just so happens the old mantra of "every 3,000 miles" doesn't apply to newer cars, so when people forget and do it at 6,000 or 8,000, there aren't any negative effects.
And I would say people don't change their oil because they know their engine will die if they go too long. They do it because it's been ingrained in their head as required maintenance, and that sort of thing is normally taken care of nowadays in a much larger package that includes filters and belts (because people vaguely remember about oil, but they're clueless about the other things.)
I'm not the one you were responding to, but my point here is that people aren't going to ensure prevention without a ton of conditioning or some greater authority forcing them to do so. The voter turnout for Australia, where people are forced by law to vote, was 93% in 2010.[0] In the USA? 41%.[1] People can't be asked to run over to their local elementary school for 20 minutes and pick the first name that pops into their head once every four years, so I doubt any sort of repercussion not mandated by law will have an effect.
Good analogy is car maintenance. Most people are very diligent about oil changes because they (inherently, I would argue) recognize the cost structure.