[falkin42]

GM also killed the Volt when its subsidies ran out, because it was no longer cost effective to keep selling.
I was mostly responding to the idea that governments have a variety of tools at their disposal to influence all manner of behavior, including behavior that can help or harm the rest of the world. That's all. The specifics require aggregate data that very few people have because it's very difficult to conduct those kinds of studies.
In the case of the electric car subsidy, there's also something to be said for an intangible benefit like normalizing the EV. Not impossible to measure for research, but not exactly quantifiable like "x% reduction in emissions" or the like.
I'm also reaching the limit of debate I can put forth. I should get to work.

One last thing, just because we can't fix everything doesn't mean we shouldn't fix anything. But that's trite, I know.