I think we can keep the positive externalities (most of them) without having (most of) the negative externalities. We have an aviation system that doesn’t actively kill anyone (due to safety issues), but still pollutes. But I believe we could have a system with alternative energy sources that did neither, with very little price uplift at scale. But now we underprice automobility(obviously) and so over consume it and so have excess negative externalities — even if you allow for a fixed value of life —, and underspend on seeking change.