Theoretically, you're right. However, when such savings occur, somehow both companies and government get their cut. Even now, governments are looking at taxing for mileage driven to make up for losses in gas tax revenues
A certain amount of revenue is required to build and maintain highways and roadways. The gasoline tax was used because it targeted those who used the roads...
If the required level of revenue is to be maintained another mechanism will have to be found to maintain the roads... Electric cars still require roads.
America's Civil engineers say that the road system is very very bad shape and could use a very significant investment beyond the current funding levels.
Both highway revenues and outlays figure prominently in the report. In the year 2000, highway-user charges made up 62% of highway revenues, but in 2010 provided only 42.5% — a direct consequence of the ongoing effects of inflation on the gas tax, state and federal reluctance to increase the tax rates, and improving vehicle fuel efficiency. The shortfall has been made up by increasing appropriations from general funds and bonds, among other sources. Of the more than $200 billion spent on U.S. highways in 2010, about half was used for capital investments and a quarter for routine maintenance and traffic services. Given the failing grades that existing U.S. roads received from the ASCE, the implication is that road expansion continues even as maintenance is shortchanged.
- See more at: http://journalistsresource.org/studies/ ... hM7yS.dpuf
There are other benefits that electric cars offer that are hard to quantify but could be substantial.
1. Reducing automobile emissions to zero with electric cars would improve air quality with the benefit of reducing health care costs... (Those of you who grew up next to expressways will understand this benefit)
2. Reducing the use of oil and gas would localize spending. Although the US is currently a net exporter of oil and gas right now, most electricity (excepting hydro electricity purchased from Canada) is locally produced.
3. reducing the dependence on oil produced from fracking, which is still a potential threat to ground water.
4. reducing noise on roads and highways. (again especially good for those raised under expressways..)
5. safer cars. electric cars in collisions are more survivable than gas cars.... Gas go boom.