Oil scarcity is not our biggest economic problem. Not even close. What scarcity there is is exacerbated by poor policy rather than dwindling reserves.
Short term, scarcity may or may not be a problem. Medium/long term, invasions of Iraq, at some point Iran maybe, and right now illegal bombing of Lybia should tell you that control of the largest available sources is playing a major role. If you don't think that is motivated by scarcity, here's some
recommended viewing.