Natural gas is not a transportation fuel as is liquid petroleum. Natural gas is like my favorate form of stationary power: nuclear.
Natural gas is great stuff but we still need to drill, drill, drill.
LNG/LPG (or is it just LPG, and LNG won't work?) has been in use as a transportation fuel for decades in Europe (don't know about other regions). The market share is certainly smaller that gasoline/diesel, but the technology is available and the infrastructure is in place, and right now it's just a cost-benefit question of having one's car adapted. When oil runs low and gas is plentiful, the balance will quickly tilt towards gas. If it's just LPG, what technical reasons are there that LNG couldn't be used as well?