Depends on the timescale. An off-shore oil platform, for example, may take years to build, place, and get operational. And nobody, not even the government, is going to pour money into oil production infrastructure (for increased capacity OR maintenance) just to let it idle. We're only going to make those kinds of investments if we plan on recouping the costs, and the only sure way to do that is turn on the taps. So we're never going to have significant extra domestic production capacity, whether or not we cut domestic output. Which means that we still wouldn't be immune to oil-price shocks from sudden output cuts from middle-east countries.
None of this is to say we shouldn't be more energy efficient, though, because that's got its own economic benefits, as does increased efficiency with regard to pretty much any resource.