Plato, the famous Greek philosopher called necessity the mother of invention. Yes, only when there's a need for something will people get creative and start thinking about how to achieve that "something".
So, I therefore declare that we absolutely NEED to see gas prices reach the $4.00/gallon threshold and stay there for a long time. Without the pressure of expensive gas, there is no need to conserve what we have or to look for alternatives. People are complacent and enjoy the lifestyle they have gotten used to in the past 30 or so years.
Yes, it might hurt for the first few years, but don't say you didn't see it coming: China and India are consuming more and more of the global supplies of crude oil every year - with no apparent end in sight. Americans are still in love with their trucks and SUVs - that's not going to change unless it becomes too expensive, or carmakers are forced to increase gas mileage in their vehicles. The only way to make change happen is by force: if we're forced to come up with more fuel-eficient cars because the current ones are too expensive, I am confident that would happen.
Another side effect of this "innovation" period would most likely be a crossover into other energy sectors: solar and wind energy, passive heating and cooling designs in new construction, new technologies and materials to create, transfer and store energy.
We may not have a World War II, a Great Depression or a Race to the Moon for our generation, but I'm thinking that expensive gas might just be the catalyst this country needs to move our energy policies forward, into the 21st century...