[yourapostasy]

As others have so aptly pointed out, externalities are the huge fly in your ointment. Rather than keep prattling on about externalities, I want to direct your attention to a practical example, environmental mercury contamination. [1] As a civilization, we knew from over 200 years ago that various mercury compounds were bad news bears in sufficiently-high quantities and/or cumulative exposures.

Industrial utilization of mercury is incredibly useful, adequate remediation and recovery expensive, and venting mercury-laden industrial waste into the atmosphere so easy and innocuous-looking, combined to land us in a modern situation any 16-18th century fisherman would find utterly absurd and fantastical. Lots and lots of people paid over many decades and centuries to have their needs satisfied with the help of mercury-laced compounds and mercury itself, to dump (and continue to dump to this day) their cumulative externality upon us, despite extremely early knowledge about cumulative effects, so that we go about our day-to-day in a real, live sci-fi world where some fish have so much bioaccumulated mercury that we have to ration our consumption of them.

There is an enormous amount of economic activity in the world today that works solely from finding and monetizing externalities. I expect this only gets worse in the future.

[1] http://www.researchgate.net/publication/272563841_Mercury_in...