It seems unlikely that oil and gas wouldn't be valued for both use as energy source and for chemical processes in the future as well. With an added benefit of less oil burnt now, might decrease the chances of a cataclysmic climate event in the near future.
It's more likely in environmental regards, that oil and gasoline will be nearly regulated out of use in the future (if they're not simply stamped out by superior energy infrastructure). The death by regulation scenario becomes more likely as the world becomes less dependent on oil / gasoline. That's why the Obama Admin dares to hammer coal now, because natural gas has come online via fracking.
