Nat gas increasing has more of a positive impact on electric vehicles in my opinion. Nat gas is source of electricity generation makes electricity cheaper, and therefore favors electric cars.
I've got a nat gas vehicle, and it is not as good as regular gas. The equipment needed to compress the gas and fill tanks as fast as a common gas pump is really expensive. You can get a home filling system for less than $5K, but it takes all night to fill the tank. Compare that to the 6min charge on the Li-V battery. Plus, driving around with a tank of compressed gas is kind of nerve wracking. (A leak or worse isn't just going to spill to the ground, if you get my drift.) The electric cars will be much more fun to drive. faster acceleration, low maintenance. JMHO