Paying for prevention makes more sense now because it would reduce large payouts, increasing profits for insurance companies. Profit motive should be an incentive for this. Removing the profit motive would remove any incentive to pay for prevention. Either way, the government could just increase taxes to pay for increased costs. Anyway, once regulatory capture is achieved (and the stakes are far to high for me to believe that won't happen), the profit motive will be back in play.

Not really. Because right now, simply excluding expensive individuals is far easier. You have more incentive to pay for prevention with universal coverage.

Again: Not sure what would work in the U.S. because there are more differences between the U.S. and Europe than just who pays the doctor's bill and there are a great many more things which impact health outcomes than how the bills are paid. Unfortunately, Americans seem largely oblivious to those facts, which is why we keep talking about who to bill rather than how to get genuinely better health outcomes.