The problem is simple and economical, the product is not just for the US customers and the pricing and profits would be based on world price and demand.
Plus a little fact that the US is a member of the WTO that states that you can only sell so much before you are forced to buy from outside the country.
Don't think for a minute that exploiting natural gas in the US will result in lower costs in the US...it's all about profit and if one customer says I will pay you X for this and you offer less, guess who's going to get it?
I'm sure that if natural gas were to actually become a fuel that was widely used by vehicles, there would have to be changes made to any global agreements on it's use and production. As with oil production, there are OPEC meetings and adjustments to regulations and agreed upon production rates.
What I like the most about the concept of natural gas for cars, as compared to hygrogen gas, is that there already is a vast infrastructure of natural gas pipelines throughout the country. I'm not against using hydrogen, but an actual hydrogen engine that will be affordable and a national hydrogen distribution system, are all a decade or more away. I say build them, but meanwhile, let's try to work with what is already available.
Besides natural gas, I am very much in favor of true hybrid vehicles. Not those sissy versions that exist today where they use electricity when driving under 25 mph, but true hybrids that can hold a 100 to 200 mile electrical charge that you can plug in at home, but also maintain that combustion engine to help with extending driving range when necessary and to allow for providing heat in colder climates.
I would hope that we see the message by Pickens is more a message of "Lets's use the resources we already have, Right Now. Yes build better things, but let's work with what we have right now."