Not really. Consumption of marginal value is...of marginal value. The US doesn't really lose much if it cuts down on fuel consumption that doesn't benefit the user very much.
For example, if people use a Prius instead of a Chevy Tahoe (reducing fuel consumption by 75%), they may have lost a little bit of status, comfort, acceleration and crash safety, but...they get to work just fine.
Similarly, if they move from a Prius to a Volt (reducing fuel consumption by another 75%, to the point that ethanol could provide all of the non-electric miles), they may pay a bit more upfront, but over the Volt's lifetime they'll come out ahead. A little frontloading of expenses seems like a pretty small price to pay, especially when a Volt (like EVs in general) has much better road performance.
There are many more examples: shipping companies may lose a tiny bit of flexibility by moving from trucks to rail; water freight may have to retrofit skysails, reduce speed a little (a 20% speed reduction gives a 50% fuel consumption reduction), and eventually go to specialized batteries which might require more stops in port for battery switching; makers of packaging may have to find ways to maintain structural strength while reducing plastic content; chemical companies may have to add a process step or two to use non-oil sources of hydrocarbons; middle income shoppers may go online, and consolidate a few trips while they're waiting for their Prius to arrive; lower income drivers will have to go to lower-status higher-mileage older small cars (whose depreciation cost is so low that it offsets higher repair costs) while they wait for Priuses to arrive in used car lots; telecommuting would make managers uncomfortable.
None of these are a really big deal - their development diverts R&D away from other productive uses, and slow the economy down a bit during the transition, but it's not TEOTWAWKI.
In the long-term, oil consumption will be strongly non-linear. Above about $80, investment grows in alternatives, especially batteries. As both R&D and manufacturing volumes increase, innovation and economies of scale are creating disruptive competitors whose costs will reasonably soon start to fall well below the old oil-based price norms - at that point oil consumption will continue to fall even if oil prices start falling.
At that point, oil exporters will be in deep trouble, and wish they had saved as many of those T-bills as they could....
