I think this will take many years to occur - conversion to natural gas is an expensive process for automakers, and it will take a long time for the public to adapt - add to that the decreased power of gas in reciprocating engines.
Ten to 20 years is my guess.
It is more expensive. The fleet is probably growing faster than you know. At $1.50 to $2.00 cheaper than a gallon of gasoline on an energy equivalent basis, a lot of people might be interested in a vehicle that could use natural gas.
It would better yet to have a multifuel setup. With enough natural gas capable cars on the road, the traditional raping of the masses when gasoline prices were routinely jacked up such as around Memorial Day and Labor Day would be a thing of the past.
When you think about it, a $1.50 to $2.00 savings per gallon would extremely appealing.
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