So we end up with everyone taking legal action against everyone else that uses a less efficient combustion engine?
You're forgetting the concept of "social standard".
Is a less efficient car "pollution"? On some level, yes. So is breathing.
What would happen if I tried to sue someone for breathing too hard? It would be thrown out as a nuisance suit, and I'd end up paying damages to the people I sued, because "we" as a society have chosen to ignore the pollution of breathing because everyone does it.
Everyone has a car, so the "social standard" does not condemn it.
However, someone whose car is belching blue smoke and smelling awful, a suit against them will win the same way that someone who refuses to turn off their stereo at night and keeping others awake could be successfully sued, without someone who plays their stereo while in the driveway working on their car being afraid of "violating noise ordnances".
I'm thinking that's not very efficient.
Keep in mind that markets tend toward efficiency. That doesn't mean that anyone's ideas of "optimum" will ever be reached, just that the incentives lead toward more efficient answers all the time.
To continue the car example, if a technological change happens, and completely clean power becomes available, someone who runs an inefficient gasoline engine might very well become open to prosecution for polluting because of the change in social standards as more and more people become accustomed to non-polluting energy.
I do value the discussion so far and have read posts with new ideas. I have a feeling the answer is somewhat fuzzy because a free market system hasn't existed for so long. There is just no real example to examine.
I find it interesting to look at those places and times where regulation is comparatively lower. Like the PC vs. the automobile. Or computer networks before and after the Internet was de-regulated.
For 20 years the 'Internet' stagnated as a toy for government, big companies and educational institutions, because of the restriction on any participation by commercial entities for the purpose of commerce.
Go look up AlGore's "Information Superhighway" proposal from the 1992 presidential race. Total government control.
Then, just before Clinton/AlGore took office, the NSF repealed their non-commercial restriction and threw open the "Internet" to anyone who could afford the cost of connecting. Within 2 years what we now know as the 'Net was alive and thriving.
Yes, a substantial quantity of the information that is now, and for that matter has been for 15 years, is "illegal" due to copyright, patent and such. But that's not a market failure. A demand is being met, that's a market success.
Granting monopoly "letters patent" by government, that's not the "market". Scratched surface, government found.