Why not Natural Gas?

Today I heard, for the first time, about cars running on natural gas. This seemed like a great idea. Natural gases are abundant, cheaper than fossil fuels, and they burn much cleaner. They are also a lot safer because the ignition temperature is about twice as high as fossil fuels. Why don't we use fossil fuels to power our cars?

After doing some research I found a couple of pages that gave me some interesting answers. This Wiki Answers page has some theories but I still think that natural gas is a viable way forward. One of the reasons was that the infrastructure for natural gas isn't in place. We don't have the filling stations to meet the demand. Also it costs around $2,000 to convert a car to run on natural gas. It seems to me both of these problems can be solved. Eventually we will run out of fossil fuels and will be forced to find an alternate fuel source. Why not start the conversion process now so that we can slowly make the change to natural gas instead of being forced to hurriedly make the conversion sometime in the future?

It seems to me that the thing that is standing in the way of natural gas right now is lobbying from the petroleum companies. They are incredibly wealthy and powerful so they can stifle any attempts to find an alternate fuel source. In my mind though, the smart play for them would be to embrace the switch early so they can be the leaders going into the future. Fossil fuels will run out so you might as well get ahead of the game. Already a lot of industrial vehicles such as forklifts run on propane. Also Honda has a natural gas powered Civic. The only problem is that there are only 800 natural gas filling stations in the U.S.