in my late teens, i worked at a gas station that had CNG...it wasn't overly expensive to convert a regular gasoline vehicle to accept CNG, and CNG was dirt cheap...i am somewhat surprised there isn't a home version CNG station available, with more thought to provide CNG powered vehicles...the beauty of CNG is the engine can run on either (switch on dash to select which mode to run in)...many homes already have NG, so surely setting up a home fill up solution should be somewhat feasible...CNG is still relatively inexpensive (as it is quite abundant), and i would imagine setting up CNG infrastructure (stations) wouldn't be overly difficult (either tap into existing NG lines or use an above ground tank, like they do with propane)...as well, perhaps even offer CNG cars from the factory, instead of hybrids...you don't need a fancy hybrid powertrain, you'd simply be using pretty much the same powertrain, but it would be fitted with a CNG tank instead of a conventional gasoline tank.
i think the conversion cost back in the days was about $3k, which wasn't too bad considering we'd drive around town all night in a Sierra 4x4 for about $5 (gasoline would have cost us at least $25).