I agree that you can get a handle on the specific problem I pointed out with externalities this way. However, there are two more hurdles: - First, you need to

I agree that you can get a handle on the specific problem I pointed out with externalities this way. However, there are two more hurdles: - First, you need to define what counts as the status quo, ie what do you measure externalities against? (But this is more of a problem in theory than in practice, I suspect.) - Second, you need to explain why Coasian bargaining isn't enough. See https://en.wikipedia.org/wiki/Coase_theorem https://en.wikipedia.org/wiki/Coase_theorem