That can't be said for certain: http://www.wired.com/autopia/2008/05/making-renewabl/
But yes, I agree with you. If oil is for some reason impossible to produce synthetically then there will without question have to come a time when we need to switch to an alternative. I think that switch will happen naturally without the need for government intervention, though. Even without a synthetic alternative I think that switch will happen sooner rather than later.