The days of super cheap and readily available liquid fuel are coming to a gradual close.
It's all uphill from here, so ALL vehicles HAVE to become more efficient. There's no way around it.
1959 is gone. And it aint comin' back.
Thank God ! Its vehicles were of indifferent quality made to poor tolerances from dubious materials. Tuneups every couple of thousand miles, along with oil/filters. Tires every ten thousand or less, brakes the same. Top end overhauls at 50-60K miles.
All vehicles have already become many orders of magnitude more efficient than their mid-20th century counterparts ! And America is awash in energy ! Its hundreds of years' supply is cheaply and readily available, (if a series of governments would quit heeding senseless demands of a small minority) and implement long-term programs encouraging of personal initiative permitting individuals opportunity to select the fuel/vehicle best suited to their needs.
IOW, Americans are starving in the midst of a cornacopia of energy solely due to the non-science rantings of yammerheads with a political agenda that includes the "America must fail" as its central theme. >Mech